Fix css for messages.

Remove redundant css classes from homepage messages.
Removed unneeded check for PCRE version.

Hopefully it won't be an issue anymore with newer CentOS versions.
Remove DebugKit check.

It's currently not ready for 3.0 and when it is we can just add it
to composer's require-dev section.
Comment out plugins section until they are working for 3.0.
Merge pull request #89 from ADmad/misc

Misc