Convert LICENSE to markdown

Luckily, someone had already done this:
https://gist.github.com/jnrbsn/708961
Move comment template into 'includes'

Also split it up into several smaller files.
Allow comment to use YAML as frontmatter, fix Jekyll compatibility, et. al.

I should really have separated these into separate commits...

* Allow YAML to be contained in the frontmatter, and have the comment
fill the "content" area of the page (this makes it much more readable!)
* Fix compatibility issue for Jekyll >= 1.1.0 - see: https://github.com/mpalmer/jekyll-
static-comments/issues/13
* Allow both pages and posts to contain comments
* Fix insignificant typo in the header comments
Change PHP to generate YAML frontmatter
Minor cleanup

Mostly formatting and prettifying
Allow the option to disable saving or sending comments from config

... along with two other options:
 * enable/disable scanning comments for spam
 * enable/disable saving found spam comments
Merge branch 'dev'