Moved most of ShapeOptimizer -> ShapeFeature.

An Env feature persists throughout the life of the env, so many optimizations can take advantage of the Shape analysis done by ShapeFeature.

Moved most of ShapeOptimizer -> ShapeFeature.
a1a2a394 · James Bergstra · 371e781f · a1a2a394
--- a/theano/tensor/opt.py
+++ b/theano/tensor/opt.py