Added new Features: Find all references, highlight usages, and rename refactoring

Also reverted to single instance of the F# mime type until the old one
is removed from MonoDevelop.  Changing the mime type affects the
parsing of files because the first mime type registered for the .fs
extension takes precedence and the ones we define here in the binding
don’t take effect.
Changed highlight usages to work on a background thread rather than UI, also added disposal cancelation
Merge branch 'master' of github.com:fsharp/fsharpbinding
Fixed number of parameters on GetReferences
Renamed getFileAndArgsFromProject to getCheckerArgsFromProject
Refactored GetReferences to use the correct number of checker parameters
Merge branch 'master' of github.com:fsharp/fsharpbinding
Disabled the Reference finder for now
Merge pull request #310 from 7sharp9/master

Added new Features: Find all references, highlight usages, and rename refactoring