Main

Adding fixed point type changes from a few weeks ago. This includes
significantly expanded tests.

Additional improvements to the fixed type. Also added a few good test
cases.

Fix minor bug in int128.h. Also add initial unit tests.

Adding int128.h header with support for GCC specific int128_t and
uint128_t types.

Additional improvements to the fixed point type. Also adding parse_test
which can be used to compare parse performance and a CMakeLists.txt.

Adding initial attempt at creating a custom C++ fixed point template.