Add ft detection for Saltfile
Merge pull request #26 from davidjb/master

Add filetype detection for Saltfile
highlight special state arguments
Merge remote-tracking branch 'upstream/pr/27'
Added include, extend, name, and names to keywords
Added highlighting for a few common misspellings
highlight include and extends as Include
Merge pull request #28 from rominf/state_special_args

highlight include and extends as Include