records: exposing record metadata revisions

(addresses #1990)

* Extends `get_record` with optional `revision` parameter
* Exposes revision for record information (metadata) tab
* Adds a config variable CFG_RECORD_REVISION_URL_PARAMETER
  with default value of "revision"

Signed-off-by: Bogdan Kulynych <bogdan.kulynych@gmail.com>
1: D205 Blank line missing between one-line summary and description
57:1: F401 'CFG_BIBFORMAT_CACHED_FORMATS' imported but unused
58:6: E126 continuation line over-indented for hanging indent
63:6: E126 continuation line over-indented for hanging indent
65:6: E126 continuation line over-indented for hanging indent
74:6: E126 continuation line over-indented for hanging indent
78:1: F401 'CFG_BIBFORMAT_TEMPLATES_DIR' imported but unused
78:1: F401 'CFG_BIBFORMAT_OUTPUTS_PATH' imported but unused
79:6: E126 continuation line over-indented for hanging indent
86:6: E126 continuation line over-indented for hanging indent
89:6: E126 continuation line over-indented for hanging indent
102:27: E261 at least two spaces before inline comment
103:28: E111 indentation is not a multiple of four
103:28: E113 unexpected indentation
104:28: E111 indentation is not a multiple of four
104:28: E113 unexpected indentation
105:28: E111 indentation is not a multiple of four
105:28: E113 unexpected indentation
108:28: E111 indentation is not a multiple of four
108:28: E113 unexpected indentation
122:33: E225 missing whitespace around operator
213: D203 Expected 1 blank line *before* class docstring, found 0
217: D401 First line should be imperative: 'Return', not 'Returns'
217: D400 First line should end with '.', not 's'
229: D401 First line should be imperative: 'Return', not 'Returns'
254: D102 Docstring missing
293: D103 Docstring missing
299: D401 First line should be imperative: 'Format', not 'Formats'
299: D400 First line should end with '.', not 'f'
299: D205 Blank line missing between one-line summary and description
357:45: E127 continuation line over-indented for visual indent
500:27: E225 missing whitespace around operator
504:5: E303 too many blank lines (2)
522:82: E225 missing whitespace around operator
564: D103 Docstring missing
570:9: E128 continuation line under-indented for visual indent
582: D401 First line should be imperative: 'Return', not 'Returns'
582: D202 No blank lines allowed *after* function docstring, found 1
582: D400 First line should end with '.', not 'g'
582: D205 Blank line missing between one-line summary and description
603:64: E261 at least two spaces before inline comment
603:65: E262 inline comment should start with '# '
610:38: E261 at least two spaces before inline comment
610:39: E262 inline comment should start with '# '
611:48: E261 at least two spaces before inline comment
611:49: E262 inline comment should start with '# '
614:24: E127 continuation line over-indented for visual indent
623: D103 Docstring missing
626: D400 First line should end with '.', not 's'
626: D200 One-line docstring should not occupy 3 lines
639: D400 First line should end with '.', not 'a'
639: D205 Blank line missing between one-line summary and description
670:57: E126 continuation line over-indented for hanging indent
677:5: E303 too many blank lines (2)
735: D401 First line should be imperative: 'Evalute', not 'Evalutes'
755: D401 First line should be imperative: 'Analyse', not 'Analyses'
755: D202 No blank lines allowed *after* function docstring, found 1
824: D401 First line should be imperative: 'Return', not 'Returns'
824: D400 First line should end with '.', not 't'
824: D205 Blank line missing between one-line summary and description
954:78: E225 missing whitespace around operator
955:54: E225 missing whitespace around operator
987:47: E261 at least two spaces before inline comment
1002:27: E225 missing whitespace around operator
1062: D401 First line should be imperative: 'Filter', not 'Filters'
1072: D401 First line should be imperative: 'Searche', not 'Searches'
1072: D400 First line should end with '.', not 's'
1072: D205 Blank line missing between one-line summary and description
1098:9: E303 too many blank lines (2)
1112:5: E303 too many blank lines (2)
1115:1: E302 expected 2 blank lines, found 1
1115: D401 First line should be imperative: 'Return', not 'Returns'
1129:5: F841 local variable '_' is assigned to but never used
1132:12: E127 continuation line over-indented for visual indent
1141:16: E126 continuation line over-indented for hanging indent
1175: D401 First line should be imperative: 'Return', not 'Returns'
1175: D400 First line should end with '.', not 's'
1195:16: E126 continuation line over-indented for hanging indent
1202:1: E302 expected 2 blank lines, found 1
1202: D401 First line should be imperative: 'Return', not 'Returns'
1202: D400 First line should end with '.', not 'e'
1234:13: E303 too many blank lines (2)
1248: D401 First line should be imperative: 'Return', not 'Returns'
1282:16: E127 continuation line over-indented for visual indent
1292:31: E126 continuation line over-indented for hanging indent
1331:17: E126 continuation line over-indented for hanging indent
1338:1: E302 expected 2 blank lines, found 1
1338: D401 First line should be imperative: 'Return', not 'Returns'
1338: D400 First line should end with '.', not 'e'
1382:1: E302 expected 2 blank lines, found 1
1382: D401 First line should be imperative: 'Return', not 'Returns'
1382: D202 No blank lines allowed *after* function docstring, found 1
1509:1: E302 expected 2 blank lines, found 1
1509: D401 First line should be imperative: 'Return', not 'Returns'
1509: D202 No blank lines allowed *after* function docstring, found 1
1536:17: E225 missing whitespace around operator
1604:1: E302 expected 2 blank lines, found 1
1604: D401 First line should be imperative: 'Return', not 'Returns'
1604: D400 First line should end with '.', not 't'
1648:28: E261 at least two spaces before inline comment
1648:29: E262 inline comment should start with '# '
1703:1: E302 expected 2 blank lines, found 1
1703: D401 First line should be imperative: 'Return', not 'Returns'
1753:1: E302 expected 2 blank lines, found 1
1753: D401 First line should be imperative: 'Return', not 'Returns'
1753: D400 First line should end with '.', not 'y'
1794:1: E302 expected 2 blank lines, found 1
1794: D401 First line should be imperative: 'Return', not 'Returns'
1794: D202 No blank lines allowed *after* function docstring, found 1
1794: D400 First line should end with '.', not '}'
1811:56: E225 missing whitespace around operator
1835:1: E302 expected 2 blank lines, found 1
1835: D401 First line should be imperative: 'Return', not 'Returns'
1835: D400 First line should end with '.', not 'e'
1864:26: F821 undefined name 'exc'
1866:22: F821 undefined name 'exc'
1869:1: E302 expected 2 blank lines, found 1
1869: D401 First line should be imperative: 'Return', not 'Returns'
1902:1: E302 expected 2 blank lines, found 1
1902: D401 First line should be imperative: 'Return', not 'Returns'
1946:1: E302 expected 2 blank lines, found 1
1957:1: E302 expected 2 blank lines, found 1
1957: D203 Expected 1 blank line *before* class docstring, found 0
1957: D204 Expected 1 blank line *after* class docstring, found 0
1957: D400 First line should end with '.', not 'n'
1957: D205 Blank line missing between one-line summary and description
1988:15: E261 at least two spaces before inline comment
1990: D401 First line should be imperative: 'Create', not 'Creates'
2025:31: E261 at least two spaces before inline comment
2053: D401 First line should be imperative: 'Return', not 'Returns'
2053: D400 First line should end with '.', not 'e'
2068: D401 First line should be imperative: 'Return', not 'Returns'
2068: D400 First line should end with '.', not 'd'
2091: D401 First line should be imperative: 'Return', not 'Returns'
2091: D400 First line should end with '.', not 'e'
2091: D205 Blank line missing between one-line summary and description
2129: D401 First line should be imperative: 'Return', not 'Returns'
2129: D202 No blank lines allowed *after* method docstring, found 1
2238:36: E127 continuation line over-indented for visual indent
2241: D401 First line should be imperative: 'Return', not 'Returns'
2298:33: E127 continuation line over-indented for visual indent
2321:37: E127 continuation line over-indented for visual indent
2366: D400 First line should end with '.', not 'r'
2366: D205 Blank line missing between one-line summary and description
2404: D401 First line should be imperative: 'Run', not 'Runs'
2404: D400 First line should end with '.', not 'k'