Import fix

- Reordered imports in a more logical way
- Uniformized notations to use tensor.* everywhere instead of T.*, basic.*,
  theano.tensor.* and theano.tensor.basic.*

changed default value of keep_type in accordance with decision from
theano-dev mailing list
added unit test to ensure that grad behaves as it is required to for
pylearn2 support

Got rid of a few "except:"

'except Exception' is to avoid catching interrupts like Ctrl-C.

A few fixes to prepare for change in grad output

I caught places where the warning about using grad w.r.t. a one-element
list was raised when running the test-suite.
This commit removes these warnings (ensuring changing the default value of
keep_wrt_type to True will not affect tests).

Note that I changed the behavior of 'test_dot_w_self'. I asked the
author (James) before doing so: it turns out it was not behaving as
intended before.

Docfix

__hash__ should take only 1 argument.

Added new option 'keep_wrt_type' to tensor.grad

This allows one to decide which behavior is desired (future new behavior
or old one) and get rid of the warning at the same time.

Print the name of the optimizer when we have it.

We disable amdlibm for nvcc. This was previously done in half.

Fix

This is a strange case as we restect the 256 bytes limits!

fix test in float32.

added arccos

Deprecated cache entries now trigger a warning

Most people should have updated their local cache by now. Making it a
warning will ensure we notice if for some reason a bug generates new
invalid cache entries.

Misc style fixes in op.py

Functions for clean interactive debugger code