Using a const Vec3& instead of three doubles for the AnisotropicBarostat API.  Still figuring out SWIG issues.
Placed MonteCarloAnisotropicBarostat into separate files
Compiles
Merge branch 'master' of https://github.com/SimTk/openmm into vec3api
Merge branch 'master' of https://github.com/SimTk/openmm into vec3api
Fixed Python wrapper for specifying the pressure as a Vec3
Merge branch 'master' of https://github.com/SimTk/openmm into vec3api
Merge branch 'vec3api' of github.com:leeping/openmm into vec3api
Merge branch 'master' of https://github.com/SimTk/openmm into vec3api
Begin implementing unit tests for anisotropic barostat.
Merge branch 'master' of https://github.com/SimTk/openmm into vec3api
Implemented unit tests for MonteCarloAnisotropicBarostat
Merge branch 'master' into vec3api