Updated tests
Removed model-based optimizers

Removed model-based optimizers such as lmOpt and glmnetOpt.  These will
be included in the "stacking" optimizers.
Mods to caretEnsemble

Now naming the error vector and took "metric" out of the results.
Added some todos
Updated readme.
Edited readme
Made a helper function for extracting predictions
Added a helper function to check models
Moved a lot of careEnsemble code to helper funs
names to colnames in makePredObsMatrix
Implemented caretStack

Need to add some more tests, and then we're probably ready to publish to
CRAN.
Broke out tests into 3 files

Also modified the stack tests to not return warnings.
Removed pbapply require
Added more tests
Rebuilt all help files
Stacking tests now done sequentially

Rather than trying to do them in parallel
Fixed make.names to return unique names
Small bugfix: names for RMSE in greedOpt
Bugfix in predict.caretStack
Bug fix for multipredict

Fixed how newdata is handled.