use a newer version of entropy

0.3 had a bug that caused it to fail to link on lots of systems.
add embeddable project pledge button

The button is designed to be hot-linked from a project's website.
This is the simple png version.

This implementation uses the Diagrams library to fill in the number of
patrons on the button template. It should be simple to adapt if the art
changes. The png file is embedded into the program at compile time, and
the png should only get parsed once and then be cached.

I have not benchmarked yesod serving up the buttons, but I expect it to be
pretty fast.
refactoring in preparation for flagging comments

Organized config/routes, and split Handler/Discussion.hs into
Handler/Wiki.hs and Handler/Wiki/Comment.hs. Merged Handler/Tag.hs
into Handler/Wiki/Comment.hs.
more comment handler refactoring, removed 'rethreaded' column
lots of comment refactoring, reworked max depth
Massive refactoring to wiki comment code. Comment flagging.

Begun unifying comment actions with a single function, though there
are some warts related to 'previewing' changes (especially new
replies), so it's not as clean as it should be.

Begun implementing comment flagging (the views still need work).

Fixed ticket SD-100 (hide permalink/parent links in preview).
changed comment box in flagging to a Markdown field
added migration14
'add tag' action only available to established users
fixed bug where unmoderated comments were shown
only show 'establish user' link on comments for unestablished users
auto-moderate all unmoderated comments of newly established users
redirect to home after accepting honor pledge
don't hide unmoderated comments from the commenter
fixed test
refactoring /newcomments
added /edit to comments
render unapproved comments on /newcomments, fixed ordering on /newcomments, prefer to show comment moderated timestamp over created timestamp
add comment delete and comment actions for edit/delete
flagging work, some model/comment refactoring