[CRASH] fix for op with make_thunk not telling if they are lazy or not.

Add tutorial test about it.
pep8
some pep8
pep8
Small fixes to the svd and lstsq ops
Fix the init/deinit of the cublas handle.
Fix missing identifier.
Return an exception status when there is an error in cublas_init() or cublas_shutdown().
Merge pull request #1998 from abergeron/fix_cublas_init

[FIX] Fix the init/deinit of the cublas handle
Fix import order that cause crash.
Merge pull request #1994 from nouiz/lazy

[CRASH] fix tutorial example related to lazy evaluation.
[CRASH] remove assert in opt and silence it as it is normal that it can't be applied.
Merge pull request #1999 from nouiz/warning_opt_upcast_elemwise_constant

[CRASH] remove assert in opt and remove print
Allow to detect if we use cublas v2 or not.
Merge pull request #1978 from AlassaneNdiaye/fix__test_cross_validation.py

Fix to the test_cross_validation.py script
Merge pull request #2001 from nouiz/cublasv2

Allow to detect if we use cublas v2 or not.
Force recompilation of all ops following cublas v2 interface change.
Merge pull request #2003 from nouiz/cublasv2

Force recompilation of all ops following cublas v2 interface change.
Fix compilation crash in mrg on the GPU.
Merge pull request #2004 from nouiz/crash_mrg

[CRASH] Fix compilation crash in mrg on the GPU.