Primer3-py

- Update `libprimer3` to version 2.3.7
- Better test coverage for low level bindings

- Fixed compilation errors, unicode-related build problems
- Fixed memory allocation / deallocation issues with mispriming libraries

- Added `misprimingCheck` function to `primer3/thermoanalysis.pyx`
- Corrected unclear syntax in C API code

- Better documentation regarding max. seq. lengths for thermo. calcs
- `calcHairpin`, `calcHomodimer`, `calcHeterodimer`, and `calcEndStability` now raise
`RuntimeError`s as appropriate

- Several major bug fixes in the design bindings pipeline
- Better testing framework for the design bindings
- New documentation system
- Better under-the-hood thermodynamic analysis abstraction

- Improved support for sequences stored in Bytes objects
- Renamed getThermoParams to loadThermoParams for clarity