Revert "Re-removed extension module (see notes for commit 3d566be)."

This reverts commit bff4b8c7e203f0e6e60a82dc5440f35c814caa6c.
Adding utility to get C streams using ctypes instead of an extension module.
Remove extension module dependency (disable print statement)
Remove extension module from setup.py
Added error handling for common import problems.
Should work on Python 2.6.
Update minivect submodule
Prototype for C string slicing in Numba.
Allow custom AST pipelines
Promote arrays and scalars, allow retrieving original python function from numba function
Fix some type inference slicing bugs & split in mixin
Refactor some stuff
Decref object temporaries & return error indicator to caller (amend)
Support object temporaries
Work on supporting slicing
Finish slicing & object temporary cleanup
FIx indexing bug
Incref object return values
Incref return value before temps are decreffed
Visit ast.Dict children, coerce numpy array attributes back to object
Implement slice assignment