Checks for preallocated output memory, take 2

Added theano.clone in the doc.

That way, we can more easily allocate an array full of zeros
of the right type.

Also use a saner way to compute the output dimensions.

All the checks will still be applied in the inner function at least once
on every input value. However, for subsequent calls of the outer
node on the same input values (for output memory checking), the inner
function call will be much faster.

That way, some instances of DebugMode can do the checks,
while others do not.

Since the contract regarding output memory has changed,
it is not guaranteed that the op itself did allocate that memory.

Also, create the memory buffers as needed.

Fixed crash in a specific concatenate situation

Mixed

Fixed bug with broadcastable flags of MaxAndArgmax

Also add test for the mul grad.

Fix a number of tests for Python 2.4

int(numpy.bool_(False)) returned False, not 0.

Also add (disabled by default) debug printing statements.

Mixed