changed the default config value of mode to Mode. That don't change the default comportement, but allow by default to take into account the theano flags optimizer and linker.

fix HostFromGpu.grad and GpuFromHost.grad return type. Probably the only impact is to remove a warning.

make it an error to have include dir into blas.ldflags as we don't use them and this could hid other include.

Also make the check about the presence of dynamic lib more strong.

Don't check if their is a dynamic lib their.

That prevents other processes from deleting this dir while it is still empty,
before the files are created in it.
That problem caused intermittent failure of some tests.

problem, but ... it could have been?