Add grappler opts and new script to compile graphs.

Usage:
  python CompileTFGraph.py --config config.json

where a sample config.json looks like this:

{
  "model_name":"full_kernel.pb",
  "input_tensors":{
      "actual_input_1":"2,245,234,3",
      "input2":"2,245,234,3"
  },
  "output_tensors":[
    "output1",
    "output2"
  ],
  "scale":10,
  "bitlength":63,
  "mode":"SCI",
  "save_weights" : true
}

Do python CompileTFGraph.py --help for seeing all the options.