Theano: Allow re-generating compiled function and improving OpFromGraph

by Chienli Ma for Python Software Foundation

This proposal will improve Theano in the following aspects. Firstly, we will provide user with an interface to re-generate and slightly modify compiled function and therefore save their time to recompile almost same function. Secondly, by improving OpFromGraph, optimizor of Theano will be able to reuse optimized FunctionGraph, whilch will save time.