Making existing dependency stuff reusable.
Fixing display when requirements not met
We should parse section headings
Plugins can now specify their own requirements
Probably should use version_compare rather than strnatcmp.
PHP version compare version number compatibility
PHP version compare version number compatibility
Ability to require idno version number
Specify plugin and versions

e.g.

plugin[] = Foo
plugin[] = Bar,1.0-dev
Merge pull request #221 from mapkyca/plugin_extensions

Plugin requirements. Awesome!