Net35

Branch supporting .net 3.5 with older version of Lucene (2.9.2.2)

No functionality difference from current master.
Additional Dependency of System.Threading 1.0.2856.0

.net 3.5 compatibility:
- Changed projects to build to .net 3.5
- Added reference to local source Lucene 2.9.2.2
- Added reference to System.Threading 1.0.2856.0 (for ConcurrentQueue object)
- Changed Lucene constants requested from LUCENE_30 to LUCENE_29
- Changed APIs where they had changed in 3.0
-- use of .Close() instead of .Dispose()
-- Occur.Must location change (inside BooleanClause)
-- TopDocs capitalization changes

Cleanup:
- Removed nuget references to .net 4.0 lucenes (2.9.4.1 & 3.0.3 in Tests, SharpZipLib [Lucene 2.9.4.1 dependency])