Added a few parameters
Added a few parameters

This commit adds an angle and an improper to the parameter file,
such that alanine sidechains may be properly parameterized. This
does not fix the issue with repetition orders not matching
between backbone-only and sidechain-included orders.

geekysuavo/ibp-ng,geekysuavo/ibp-ng,geekysuavo/ibp-ng,geekysuavo/ibp-ng