fix bug that breaks MATLAB 2014a compilation
Merge pull request #696 from rbgirshick/matlab_2014a_fix

Fix bug that breaks MATLAB 2014a compilation
use layer_param instead of layers_[layer_id]->layer_param()
Add param_propagate_down_ vector to layer, populate according to
blobs_lr in Net::Init
Make ConvolutionLayer and InnerProductLayer abide by param_propagate_down_
Use Blobs instead of SyncedMemorys for the bias_multiplier_'s.