Added members to generate checker options for script and project specific options separately.

GetCheckerOptions has a little too much responsibility dealing with
both script and project options, both of which have mutually exclusive
parameters.  Ive initially split this out so that you can call for
script or project options separately.  Maybe this could be marked
obsolete and refactored in the future.
Added checker invalidation for file add/remove and reference add/remove.  This increases the validity of the results from the language service.

Removed ActiveDocumentChanged event subscription as the
TypeCheckService already requests a reparse of the active document when
it changes.
Merge pull request #355 from 7sharp9/projectinvalidation

Added project invalidation to resolve bugzilla 17796