Merge pull request #176 from opensim-org/fix_memory_leaks

Fix memory leaks in AssemblySolver and misuse of SimTK::XML, testInitState should pass now on windows
Merge remote-tracking branch 'remotes/origin/master' into matt_ayman_frames
Make sure Frames are "connected" to Model after deserialization, fix a couple bugs and beef up test case testFrames to test serialization/connection