Partial enable of GPU max/min for 010 pattern, (and so 1000, 0100, 0010 and 0001) by reshaping.
Finish implementing GPU 010 min/max.

This probably fix a the bug in the not enabled implementation: 010_inner
Add direct GPU min/max reduce for pattern 1, 11, 111, 1111, by by reshape for 11111*.

Also add test that other GPU min/max that are done by reshape.
Add NEWS_DEV.txt file.
more error info in test.
Implement all missing case of GPU min/max that was supported by GPU sum.

This mean the not available case 1010, 1011 and 0111. The following case where implemented with reshape for min/max, but not for sum:110, 001, 0011, 100.
pep8
update the dev news.
Remove fct not used anymore.
remove old code. This particular fct support all cases.
Add gpu prod implementation.
code clean up.
remove import not used.
More error message in tests.
Merge pull request #1457 from nouiz/gpu_min_max

Gpu min max, more pattern implemented