Gpu cholesky

Always import gpuarray.rng_mrg to have its optimizer imported.

Use Op params for GpuDnnSoftmax

move buildbot cache outside workspace

Better error message when an opt make an invalide replace.

Unsigned char:  fix: theano/scalar/basic.py

change default dnn path on windows

Do the review, add support to recreate the error with just an error message as some error handling code append to existing error message.

Changes to GpuEye to enable `k` offset parameter.

Remove call to GpuKernel_init with binary

As it is trying over and over to compile it as source.
Also, start removing generation of binaries from Theano.

Disk cache option for gpuarray

Important update, necessary to make enums inside ParamsType
work correctly with Python 3 (as we need enums C support code
for PyInt_AsLong/PyLong_AsLong support).

 - algo (C enum)
 - mode (C enum)
 - handle (handle_type)

Extend DnnBase.get_params() to take ParamsType into account.

Update ParamsType usage in `theano/gof/op.py`.

Add public:
 * has_type()
 * get_field()
 * get_enum()
 * enum_from_alias()
 * get_params()

Update documentation for ParamsType.

Add public: fromalias(), has_alias().

Update documentation for enumeration types.

Implement new op param type `EnumType`