winograd fast R-CNN, new dataloader

• VGG16 based Fast R-CNN model using winograd kernels
• new, backward compatible, generic data loader
• C3D video loader model trained on UCF101 dataset
• Deep Dream example
• make conv layer printout more informative [#222]
• fix some examples to use new arg override capability
• improve performance for relu for small N
• better support for arbitrary batch norm layer placement
• documentation updates [#210, #213, #236]