Moving Collection, Stream and Keep classes into their own files
Renamed Keep/Stream/Collection submodules to keep/stream/collection (lower case)
Added Python SDK section to documentation
Script to build python documentation (requires epydoc)
Moved Python SDK and crunch utility scripts pages to SDK Reference section.
Fixed path to glyphicons
Started tutorial on running external programs
collection.py import stream
Removed "Tutorial:" from titles since that was an artifact from before we had improved the navbar.  Also fixed typo in tutorial-trait-search.
New tutorial for running external programs
Fixed import problems due to splitting module into multiple files
Merge branch 'master' of git.clinicalfuture.com:arvados
Merge branch '1911-python-sdk-pydoc'
Merge branch '1868-tutorial-running-binary-progs'