conv.cu simple comment fix

GpuJoin takes negative values for axis

Small changes.

Adding clang-omp++ as an alternative compiler to clang++ as it suppots OpenMP

fix gh-4305

fixed nosetest doc

Gpupool newbackend

Make sure the input of Neg.impl is not a numpy.bool_

small fix: doc, assert -> python error, printing, code clean up.

Add local_zero_div to specialize phase

Added required __future__ imports

add R_op for DisconnectedGrad

Otherwise, -False is True, and -True is False.

Add a test that this is enough to solve the binary_crossentropy(reshape) case.

Add optimizer merging two switches of same condition

[MRG] UnicodeDecodeError exceptions due to accents

Fix problem with python 3.5.