Theano _print_Derivative uses theano.tensor.Rop
_print_MatrixSlice -> theano.Subtensor
add theano_simplify to test_theanocode. fix deriv
BlockMatrix -> theano.tensor.join
block_collapse handles inverse, transpose.

Also uses bottom_up instead of top_down
remove incorrect block_collapse inverse test
style refactor BlockMatrix._eval_inverse
integrative test for theano, blockmatrix, inverse
Latex _print_MatrixSymbol = _print_Symbol
test bc_transpose
Merge pull request #1965 from mrocklin/theano-derivative-rop

Theano matrix printing and Derivative