Merge pull request #24 from rgrinberg/master

Tiny fix for obuild to print all missing dependencies at once
Don't forget annot modes when doing a pack compilation.
fix typo in exception name.
add a get_destdir.
unimplemented is fatal. exit at the end.
basic lib install.
misc removal.
don't pass the cmd args to the cmd callback.
add a stub get subcommand.