Fix blas tests

C code for integer division

Minor stuff

Thanks Olivier :) Is great to have someone like you involved in the project, that is able to notice and fix all the small details. 

additions and improvements to blas on both CPU and GPU (including GEMV, GER in blas_c)

Remaining scan errors

We should use optimization tags to enable, disable them. This also could cause problem on test in case there is a bug, teardown would not be executed per James comments.

It seems that even the last fix of the generated random numbers didn't do
the trick. The reason being same numeric instability.
I've change the operation to a sum, which, if you apply it recursevly is
less problematic then multiplying numbers

Fixed crash at exit time if cache was deleted

Fixed some tests broken due to exception verbosity

Also use textwrap.dedent to avoid adding indentation to the final C
code.

This commit also includes a few PEP8 fixes.

This test fails because of small numbers (the gradients are especially
susceptible to small numbers). Increasing the range from which we sample,
it doesn't mean that there will not be a seed there for which the sampled
numbers are small enough (or a few entries are small enough) to get in that
instability region

This tests are of the sandbox of scan that I want to change anyway..