Seed HingeLossLayerTest; bad values can cause test (and therefore Travis
CI build) to fail
Merge pull request #685 from jeffdonahue/seed-hinge-loss-test

Seed HingeLossLayerTest; bad values can cause test (and therefore Travis build) to fail
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.