Initial work for pickling Overloaded objects, with some limitations (issue #795).
Refactor pickling helpers into a separate module
Add closure support. Cell variables are frozen (as they are when JIT compiling).
Add support for globals in unpickled Overloaded objects
Add a test for a closure calling another closure
Add a test for unpickling from an independent process
Merge branch 'master' of github.com:numba/numba into pickle_dispatcher

Conflicts:
	numba/dispatcher.py
Merge branch 'master' of github.com:numba/numba into pickle_dispatcher
Add two docstrings
Merge pull request #807 from pitrou/pickle_dispatcher

pickle Overloaded objects, with some limitations