Primer3-py

- 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`
- (POTENTIAL 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`)

- Fixed incorrect tm/salt correction method lookups in `calcTm` function in
both bindings and wrappers

- Addressed bug in mispriming/mishybridization library parsing in which
memory for the global parameters struct was not being properly allocated

- Corrected several potential sources of memory leaks in the C API design
bindings.

- Corrected issue with parsing `"SEQUENCE_PRIMER_PAIR_OK_REGION_LIST"` as a
python sequence object. `"SEQUENCE_PRIMER_PAIR_OK_REGION_LIST"` should now
be provided as a list of lists or tuple of tuples (or a combination of the
two). -1 should be used in the case where an index is ommitted. For example:


Primer3 boulder IO input: 100,50,300,50 ; 900,60,,
Primer3 python input: [[100,50,300,50], [900,60,-1,-1]]

- C API path fix