Fix opt crash of local_gpu_lazy_ifelse.

NEWS.txt:
- Fix opt crash/disabled with ifelse on the gpu (Frederic B, reported by Ryan Price)
- Fix Error reporting with GpuConv (Frederic B., reported by Heng Luo and Nicolas Pinto)
- On error during execution of an Theano function, now always print the apply node, its inputs shape, strides and types. If Theano flags exception_verbosity=high, also print debugprint(op, stop_on_name=True, print_type=True)

not news.txt:
- make iadd on the gpu work on GTX285 with 6 dims
- fixes to test