optimization

Fix corner case in cvm updates, add test.

Fix wrong results that could end up with wrong shape.

The bug appeared when some shared variable was updated with itself, the
values of update expressions would be assigned to incorrect shared
variables.

Rewrite squeeze and delete SqueezeOp.

Move optimization to opt.py.

Fix BinCount output dtype. It is intp of double depending of the input.

Shape tensor basic2

Consider numpy.memmap a valid type for TensorType

Remove old init parameter that was removed in the past. Recently, we added new one. So there was a conflict.

Also assert that the output dtype if float64.

This is not important as the Mean op is not used by default.

A reshape fix this problem, but return the wrong results.

add infer_shape to AdvancedIncSubtensor and add tests; repair infer_shape of Reshape allowing for constant desired shape with possibly one entry equal to -1 and add tests

Join: added test on second axis;  TensorDot: added axes ((0, 1), (1, 0)); MaxAndArgmax: removed TODO comment