Support ordering pages and articles when iterating in templates.
Order can be set to a metadata attribute or a sorting function.
Default to order by slug for articles and order by filename for pages.
Add test for PAGE_ORDER_BY
Merge remote-tracking branch 'remotes/malept/davidmarble-page-order-by' into davidmarble-page-order-by

Conflicts:
	docs/settings.rst
	pelican/generators.py
	pelican/tests/test_generators.py
Add missing methods
move {ARTICLE,PAGE}_DIR -> {ARTICLE,PAGE}_PATHS

Instead of one path a list can be given. This is due to popular request.
Should help people not wanting to use Pelican for blogging.
Maintain backward compatibility though.
Thanks to @ingwinlu for pointing out the change in StaticGenerator.
Fix #1344 move PLUGIN_PATH -> PLUGIN_PATHS

Pelican uses *_PATHS names for settings that represent a list of paths.
Add {PAGE,ARTICLE}_PATHS to {ARTICLE,PAGE}_EXCLUDES automatically

This makes it easier for someone to change PAGE_PATHS without the
need to change ARTICLE_EXCLUDES accordingly.
Address code review comments from PR getpelican/pelican#1348

The text about the sort-by-key function comes from:
https://docs.python.org/2/library/stdtypes.html#sequence-types-str-unicode-list-tuple-bytearray-buffer-xrange

Minor style cleanup as well.
Docs update for *_{previous|next}_page variables
Merge branch 'master' of https://github.com/getpelican/pelican into davidmarble-page-order-by
Addressed comments from @avaris in PR getpelican/pelican#1348
Merge pull request #1362 from avaris/neighbor_pages_docs

Doc update for *_{previous|next}_page variables
catch arbitrary exceptions during cache unpickling

It is hard to forsee what could be raised.
Require six version 1.4.0 or later.

six.moves.urllib.parse is available since version 1.4.0.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
Use six.moves.urllib.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
Remove AsciiDocReader from core. Fixes #1355
Merge pull request #1370 from omasanori/six-version

Require six version 1.4.0 or later.
[coveralls] Exclude tests from coverage
Merge pull request #1376 from avaris/remove_asciidoc

Remove AsciiDocReader from core. Fixes #1355
Merge pull request #1322 from smartass101/get_files_multiple_paths

move {ARTICLE,PAGE}_DIR -> {ARTICLE,PAGE}_PATHS and correlate with {ARTICLE,PAGE}_EXCLUDES