Having a boost directory in the repo causes git to see the directory as modified when CMake external project updates.
Ignore teem external.
Use Boost 1.54 (temporarily) for OS X builds until 1.56 is available. Necessary because boost atomic does not build with the latest clang.
Merge remote-tracking branch 'origin/master' into teemExternal
Add Teem external project to CMake build. Minor corrections to external project settings in zlib, which is required by teem for compressed nrrds.
Enable code ported from SCIRun 4 that depends on Teem.