Adding support for mediawiki highlight

* Highlight scheme taken form:
http://en.wikipedia.org/wiki/Wikipedia:Text_editor_support#.24HOME.2F.vim.2Fsyntax.2Fmediawiki.vim
Added mediawiki support and bash like wildmenu

* Added mediawiki file type
* associated highlight and spell check by default to media wiki files
* Switched wild menu behaviour for a more bash like
Merge branch 'vim_ctags'