Documentation clarification for loading tmux project files, doc fix.
Docs: fix term linking to pane in codedocs
Support for relative start_directory when loading outside of cwd (work in progress

- behavior of .expand to honor os.path.expanduser at the time of expansion, rather than when building.
- expandpath function
- tests, docs
Merge pull request #82 from tony/project-dirs-relativity

Merge pull request for loading projects outside of current working directory. Support for expanding env variables and tildes in ``start_directory``.
v0.1.12