Implement limited function composure.

The function commited here is no where near as genral-purpose monadic--or
approximate--approach can provide. That's okay, for now.

Signed-off-by: Brian L. Troutwine <brian@troutwine.us>
Minor spelling fixes in fe_tests.erl.

Signed-off-by: Brian L. Troutwine <brian@troutwine.us>
Merge pull request #14 from blt/compose

Implement limited function composure.