add modalities and convert Caffe modalities

[jtang10]

• Add tensorflow modalities.
  • semantic segementation (NOT TESTED)
  • convert Caffe to tf model.
  • object detection
  • GAN (pix2pix). issue #16
• Write scripts to automate mudane tasks for reuse.
  • downloading
  • generating yml
  • uploading models to s3 for repetitive works.