Merge pull request #3812 from gliptak/patch-1

correct FRED test (GDP changed ...)
Merge pull request #3813 from gliptak/patch-2

remove unused import in test_yahoo
Remove unneeded import from test_google
Implement _get_hist_google
No current finance data from Google
DOC: filter the correct warning for unique(key, column)

DOC/CLN: clean up indentation and dispatch on numpy version
DOC/BUG: fix overwriting of 'df' variable in doc build
DOC: give deprecation warning about future timeseries broadcasting behavior

DOC/CLN: cleanup
Corrected typo in data
Change google finance tests to @network only
Tag yahoo data tests as @network only
Merge pull request #3815 from cpcloud/doc-build-fix

DOC/BLD: Fix a bunch of doc build warnings that weren't being previously caught
CLN: conform read_clipboard / to_clipboard to new io standards

     removed to io.clipboard (from io.parsers)
Merge pull request #3824 from jreback/clipboard

CLN: conform read_clipboard / to_clipboard to new io standards
Merge pull request #3814 from gliptak/googledata

Implement historical finance data from Google Finance
DOC: release note for #3814
Merge pull request #3816 from gliptak/patch-1

Tag yahoo data tests as @network only
BUG: missing imports for clipboard
BUG: missing imports from clipboard 2
TST regression tests for GH3836