Fix multinomial expectation and variance
This release primarily fixes how expectation and variance was shown in the multinomial distribution (#14). In particular, @faridcher contributed the following changes:
- Use matrix instead of scalar form for multinomial (b0a8912)
- Exclude *.gz files created during compilation (3b30e26)
- Add missing d\theta in posterior mean (af30a34)
- Add constraint on Students't expectation (7d0082e)
This release also improves the build process on Windows (#15).