Merge CumsumOp/CumprodOp into CumOp

Fix tests when floatX=float32.

Update checking of integer types. 

in a `grad()` function.

Add Theano flag cmodule.age_thresh_use

This fixes issue #5274.
For integer types, any string-based type-checking is replaced with a list-based type-checking using the type lists provided in `theano.tensor` (int_dtypes, uint_dtypes, integer_dtypes, etc.).

NB:
* Module `theano.sparse` have its own type lists, so they are used in this module instead of `theano.tensor` lists.
* I have tried to check the types with `discrete_dtypes` where it seems relevant (e.g. in `grad()` functions), but further analyzes may be required. That is the type list to use to fix issue #5274.

fix small python 3 compat issue

but why travis can't detect this?

Handle zero-length dimensions in GpuDnnSoftmax

Minor inconsistency in AbstractConv_gradInput implementations

Fix a test in DebugMode

Use a default value compatible with broadcastable of type

Remove printing in test.

Add testing (from issue #4834) to PR #5336.

[WIP] Use __call__ instead of make_node to avoid bypassing test values

Cleanup numpy min version

Fix warning/detection on tx1. I suppose it is an update to there comp…

Improve MissingInput message

Sphinx doc/conf: latex_font_size is deprecated

Fix warning/detection on tx1. I suppose it is an update to there compiler, as from memory, it working in the past.

* Add info on which input of the node has not been provided as input of the function