SWIG build for OSX

not sure this will actually work except on the computer I used to
compile it…seems like perhaps the paths to the swig files (in
swigosx/share) are stored as absolute paths in the binary? Need to test
on a second machine.
OS X version of python API

- scripts in /build will run swig and produce python .so module,
install in /distrib
- top-level script build_pthon_distrib.sh runs build & package scripts
- current /distrib version checked in
- added python/examples/run_example.sh, takes example # as command-line
argument, sets up correct PYTHONPATH before running

- TODO: verify that change to build/setup.py will work on windows
(possibly need to update .bat file to copy StoredCommands.cpp into the
build folder)
build fixes for windows
Merge branch 'osx_python'