Configure footnote rendering.

- The config file can provide FootnoteAnchorPrefix, which will be used
  by blackfriday when rendering to HTML. A value of `q:` has the effect
  of making the anchor for a footnote `[^footie]` be `fn:q:footie`. The
  default is `""`.

- The config file can provide FootnoteReturnLinkContents, which will be
  used by blackfriday when rendering to HTML. A value of `^` has the
  effect of making the return link be `^` instead of `[return]`.
Make each generated page’s footnotes unique.

If content pages are fully rendered in a list page, footnotes that use
the same reference (`[^fn]`) will have duplicated anchors. This change
builds on #526 to put the page filename (`Page.File.Name`) as part of
the anchor for a footnote.

This would fix discussion [116](http://discuss.gohugo.io/t/footnote-references-are-duplicated-on-list-pages/116).
Use md5 against the file path for uniqueness.
added In and Intersect template functions
Feed the titleized taxonomy key through string replace to replace '-' with ' ' for proper display of the taxonmy title
#462 fix, remove leading and trailing dashes from urlized slug. includes test changes
Minor fix to error message when copying static files
handle https prefixes in baseUrl
add 'width' parameter to 'figure' shortcode
Document manual breakpoint of .Summary

The use of <!--more--> to set the breakpoint for the generated page summary is mentioned in a release note, but not in the doc itself.

Very useful - and it leaves the formatting in place.
Minor proofreading corrections to Hugo docs

- Add backticks and commas where necessary
- Remove some trailing whitespace
- Add front matter example in TOML
- Fix typo in one of the tags in Showcase
- Add 多说 (Duoshuo) as an alternative to Disqus
- Use internal links (i.e. without gohugo.io) where possible
- Use a colon to set off an example
- Change "it's" to "its" where appropriate
- Use typographical (i.e. curly) apostrophe on the front page
  where appropriate
- Capitalize "Github" as "GitHub"
added docs for 'intersect' and 'in' template functions
Add nil-check to Intersect

The Intersect template-method would fail if one or both of the lists were nil (post vs page; post has tags, page has not).

This commit adds a nil-check and returns an empty result if any of the inputs are nil.

See #537
Fix spf13/hugo#467. RSSLink now point to index.xml
Make First accept any int

TOML and YAML handles integers differently, creating issues when using integer values from configuration or front matter in the First template function.

This currently works in YAML (parses into int), but not in TOML (parses into int64).

This commit modifies First so it accepts any int.

Fixes #551
Copy content from archetype

Prior to this commit only metadata were copied from archetype on content creation.

This commit includes the content if set in archetype. This is useful in situations with similar page structure.

Fixes #556
Set Content-Type for livereload.js

The Content-Type was not set for livereload.js and was interpreteted by the browser as text/plain.

This commit sets it to application/javascript.

Fixes #562
Big refactor of how source files are used. Also added default destination extension option.
Improved error message when config file not found.
Initial Handler Architecture WIP