readers: Split parse_path_metadata from read_file

For easier re-use.  I also extract the path metadata first, so
metadata explicitly listed in the file contents will take precedence
over metadata parsed from the filename.
Add the PATH_METADATA setting

Sometimes the base filename doesn't have everything you need.

Remember that os.sep is platform dependent, so using it in a regular
expression for this setting may not be portable (boo MS Windows!).
contents: Add URLWrapper.__repr__

This makes it easier to troubleshoot collections of URLWrappers,
because printing the collection will give you something you can
actually read ;).
Merge remote-tracking branch 'upstream/master'
Merge pull request #771 from wking/urlwrapper-repr

contents: Add URLWrapper.__repr__
Add a period archives feature and brief docs.

Allows users to have per-year, per-month, and per-day archives of posts
automatically generated. The feature is disabled by default; to enable
it a user must supply format strings for a period's respective
`_SAVE_AS` setting.
Multiple Social icons

aboutme, bitbucket, google-groups, hackernews, reddit,
slideshare, speakerdeck, vimeo, youtube

Also, fix spacing below a line-block.

Try this in resT::

	| First line
	| Second line
	| Third line

	New paragraph.

	Another paragraph.

Notice how the line-block runs into the first paragraph without the new CSS.
Creating a more explicit error message at server creation
External resources should be scheme-independent

By using "//" instead of "http://" when referring to external resources
such as fonts (e.g., from within CSS files), warnings about "insecure"
content can be avoided.
documentation for IGNORE_FILES
Adding a message for gracefully shutting down dev server
Added missing JINJA_FILTERS documentation
Added missing SITESUBTITLE documentation
Fix typos
Merge pull request #779 from johnmastro/add-period-archives

Add period archives
Merge pull request #785 from wraithan/docs_for_ignore_files

documentation for IGNORE_FILES
Fix typos
Merge pull request #786 from noirbizarre/more-documentation

Add missing documentation for JINJA_FILTERS and SITESUBTITLE
Raise exceptions from the autoreload loop if debug is enabled
Add help directly to publishconf.py