Add beta_jan25 energy function (#548)
The aim of this PR is to add `beta_jan25` to the `rosetta` source code. This is an updated version of `beta_nov16`.
We will shortly post a manuscript describing how we developed `beta_jan25`. They key updates are to the LJ potential. We identified steric clashing in proteins that were relaxed or designed using `beta_nov16`. We identified examples of this problem in a high-quality benchmark from the `dualoptE` protocol used to train the energy function. We then used this benchmark, and the others in `dualoptE`, to refit a small number of LJ parameters. The refitting largely eliminated the clashing problem, and `beta_jan25` is as good or better than `beta_nov16` when assessed on multiple benchmarks using validation data.
Frank also advised me that -gen_potential should stay the same (on top of beta_nov16), and we decided to have plain -beta invoke beta_jan25.