Merge github-linguist-grammars into github-linguist

Now that all our grammars are licensed (or grandfathered in), we can
distribute them as part of the standard github-linguist gem. This makes
it easier for projects to get up and running with Linguist.

lib/linguist.rb

@@ -1,5 +1,6 @@
 require 'linguist/blob_helper'
 require 'linguist/generated'
+require 'linguist/grammars'
 require 'linguist/heuristics'
 require 'linguist/language'
 require 'linguist/repository'