libprimer3 refactor, compilation fixes, API formalization

-Fixed memory leak in global param struct allocation for design bindings
-Integrated C API patch code into libprimer3
-Refactored libprimer3 to pure C (khash lib is now used in lieu of hashmap)
-Corrected many minor compiler warnings in libprimer3
-[POTENTIALL BREAKING CHANGE] Refactored thermodynamic alignment bindings to
always return a thermoresult namedtuple (in the previous embodiment, if no
structure was found, the return value was None)