examples: Remove example code

The example code on the website was difficult to keep up-to-date.
Instead, the website now links to the examples directory in the source
repo on github, which is always up-to-date.
Remove api.html

This page was no longer used.
features: Fix link to waffle_config() documentation

Link to the manpage, not the header file.
index: Update links to git repos

Waffle's git repos are moving from Freedesktop to Github.
man: Update man pages

Update to waffle commit bdd61ed7.
Replace Trello with the issue tracker on Github