Add user warning to prevent issue #5143

mixed

removed pruner function of EquilibriumOptimizer class

While looking for subsamples I have detected duplicated values for test_shapes in `test_dnn.py` both in old and new backend. I remove the duplicate.

* Remove the "[new backend]" part of the message and idem in the old back-end.
* Move the check to the make_node of the ops.
I'll continue analyzing the subsamples.

Show user warning in old and new backend when Theano flags `dnn.conv.algo_bwd_filter` is not `none`, to help user prevent the issue #5143.

Fix theano scripts on windows

make tensor.join() return the input when there is only 1 variable to join.

Use Scan.L_op instead of Scan.grad() to help speed up the second deri…

Fixes

numpy 1.12.0rc2 compatibility fix related to variable typecasting

Switch gs and ls to follow libgpuarray.

when g++ is not detected but the user has not set the cxx flag.