Removed the PatriciaTrieConstants module as it is no longer used anywhere.
Fix HashMap test so the project can be compiled with F# 3.0 / VS2012.
Fix documentation comment so it renders correctly.
FsUnit isn't being used in the test project any longer. Removing it to fix an issue where a bunch of tests were failing on some machines due to a versioning issue with NUnit 2.6.3 and the older version of FsUnit we'd been referencing.
Implemented an optimization for the 'mask' function in the BitOps32 and BitOps64 modules used by the Patricia trie-based collections.