TestIterSolve tested solve's argument types, not itersolve's
Fix #3: Add ability of (iter)solve to take generic iterables as clauses

This reduces code redundancy in pycosat.c's add_clauses function.
Remove redundant setting of TypeError when clauses isn't an iterator

According to the CPython API, PyObject_GetIter sets a TypeError without needing
it to be set again by the calling code.
White space
Teach solve/itersolve to accept clauses as general iterables

Commit fdf54a86bfe201fe5a465354b7b19a03f62471f4 taught them to accept the list
of lists that represented clauses as any iterable of lists. Now it can be any
iterable of any iterables.
Add a test to ensure a bad iterator won't segfault pycosat.c's add_clauses
Test non-list iterable arguments on itersolve
Merge pull request #4 from wkschwartz/iter-type-check

Teach (iter)solve to take generic iterables of iterables as clauses argument