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
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.
Merge branch 'master' of https://github.com/getpelican/pelican into davidmarble-page-order-by
Addressed comments from @avaris in PR getpelican/pelican#1348
Add timezone to datetime objects. Refs #962.

Based on https://github.com/getpelican/pelican/pull/977, but it adds
timezone information before formatting.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
Fixes wrongly generated relative urls for pagination.

When `RELATIVE_URLS` is `True` and the `PAGINATION_PATTERNS` adds folder to the path, the relative urls to these pages does not respect these additional folders.

Example:
	Settings:
			RELATIVE_URLS = True
			PAGINATION_PATTERNS = (
					(1, '{base_name}/', '{base_name}/index.html'),
					(2, '{base_name}/page/{number}/', '{base_name}/page/{number}/index.html'),)

	Theme:
			<link href="{{ SITEURL }}/theme/css/style.css" rel="stylesheet">

If you are on page 2 then "{{ SITEURL }}/theme/css/style.css" expands to "./theme/css/style.css" instead of "./../../theme/css/style.css".

Fix:
Simply compute the relative url from the paginated url instead of the not paginated one.
Fixes #1395: extends pelican.utils.strftime with `-` prefix to strip leading zeros

Adds the ability to use `-` prefix with C89 format codes to strip any
leading zeros.
Refactor logging handling

Old system was using manual string formatting for log messages.
This caused issues with common operations like exception logging
because often they need to be handled differently for Py2/Py3
compatibility. In order to unify the effort:

 - All logging is changed to `logging.level(msg, arg1, arg2)` style.
 - A `SafeLogger` is implemented to auto-decode exceptions properly
in the args (ref #1403).
 - Custom formatters were overriding useful logging functionality
like traceback outputing (ref #1402). They are refactored to be
more transparent. Traceback information is provided in `--debug`
mode for `read_file` errors in generators.
 - Formatters will now auto-format multiline log messages in order
to make them look related. Similarly, traceback will be formatted in
the same fashion.
 - `pelican.log.LimitFilter` was (ab)using logging message which
would result in awkward syntax for argumented logging style. This
functionality is moved to `extra` keyword argument.
 - Levels for errors that would result skipping a file (`read_file`)
changed from `warning` to `error` in order to make them stand out
among other logs.
 - Small consistency changes to log messages (i.e. changing all
to start with an uppercase letter) and quality-of-life improvements
(some log messages were dumping raw object information).
Corrected typo to improve readability
Allows Typogrify to ignore user specified tags. Refs #1407

Typogrify interferes with certain sections of the output that it should not touch (see #1407 for more details).
This feature adds a setting called TYPOGRIFY_IGNORE_LIST which is a list of tag for Typogrify to ignore.

The following was updated:

 1. readers.py - if TYPOGRIFY_IGNORE_TAGS is present, then use it
 2. settings.ps - default TYPOGRIFY_IGNORE_TAGS to []
 3. contents/article_with_code_block.rst - an article with a code block for typogrify to ignore
 4. updated tests
 5. updated documentation
Documents DOCUTILS_SETTINGS and initializes it. Fixes #1425
Merge pull request #1371 from omasanori/tz

Add timezone to datetime objects. Refs #962.
Merge pull request #1418 from willingc/fix-doc-typo

Corrected typo to improve readability
Merge pull request #1412 from avaris/refactor_logging

Refactor logging handling
Updates docs for Python 3

In Python 3, the simpleHTTPServer has moved into the http module, so the command `python -m simpleHTTPServer no longer works. This minor change adds instructions for those of us using Python 3.
Adds reference to SLUGIFY_SOURCE

When working on my site, I wanted SLUGIFY_SOURCE, but I came across PATH_METADATA first and enabled that for a while. Better to include the cross-reference where people can find it.
Merge pull request #1411 from barrysteyn/typogrify-ignore-list

Allow Typogrify to ignore user specified tags. Refs #1407