Simplify build process

@cap @stephentu 
Or three versions:

- `distributions`: -g -O3 -fno-omit-frame-pointer -DDIST_DEBUG_LEVEL=3 -DDIST_THROW_ON_ERROR (used in python and data microscopes)
- `distributions_debug`: -g -O3 -fno-omit-frame-pointer -DDIST_DEBUG_LEVEL=3 (used in loom_debug)
- `distributions_release`: -O3 -fomit-frame-pointer -DNDEBUG=1 (used in loom_release)