Added momentum regularization to finetuning, just needs a switch to mod_updates for the update tuple list.
simplified momentum updates for pretraining and finetuning SdA models, and moved the learning rate to be a shared variable to make decay simpler.
fixed numpy attribution bug
Oops!  Forgot to pass the learning rate  shared var into pretraining.
lowered LR, added more debugging info.  Maybe there still are pickling problems?
forgot to build decay_learning_rate in both tests
grr, type mismatch error
tweaked test values a bit
Merge branch 'adaptivelr'

Cleaned up how momentum is implemented in pre-training (and eventually in fine-tuning).  But more needs to be done in examining why my pickling tests fail.  This work can be carried out in a different branch though.