Feature freeze on non-glmnet functions

The following functions have the initial required functionalities
written, tested, and documented:

• adf: abstract data frames
• iolm: linear models
• ioglm: generalized linear models
• lars: linear path solution for lasso/lars
• lp: Lp regression, for 1 <= p < 2
• pcr: Principal component analysis regression
• lm.ridge: Ridge regression
• rlm: Robust regression, M-estimation with Tukey bi-square

Once iolmnet and ioglmnet are finished, we should be ready for a stable release.