Forward test value in clone_float32

uses inplace as op params for GpuGer, GpuGemm, GpuGemmBatch and GpuGemv

Jenkins mac buildbot

Scaled Exponential Linear Unit (SELU) activation

Repair tests that fail with compute_test_value.

(small improvement) Remove Python loop from GpuContiguous's C code.

Fix tests that always expect a C compiler

Fix some problems with the GPU

Separable convolutions

Small issues fixed.

Fix for GpuAdvancedIndexing

Added convenience function for solve_symmetric. Moved the Op lifter for Images2Neibs in opt.py such that it is included in the optimisation passes. Closes #6158

Fix strides when using dot inside gemv

Docstring improvements