Make platform-dependent compiledir configurable

Cudandarray setitem

Minor stuff

This call cudaMemset under the hood, needed for Scan on gpu.

Although it probably works under Windows with /, using os.path.join is a better
way to define paths.

@pascanur fixed bug that made scan fail to compile on gpu in some cases

Bug subtensor merge

New scan [work in progress]

Make theano.version functional regardless of whether setup.py has been run

test for the recent fix for one optimization of scan

Fix scan savemem

test for the recent fix to R-op

This refers to a bug report by Justing Bayer on 12/22/11 on the
theano-users mailing list.

added verbose exception for elemwise perform

fixed bug where ifelse rejected sparse types

objects

Scan grad computation fixed

Cvm runs testsuite

improved doc for get_debug_values

removed extraneous space

Fixed crash when theano.version does not exist

This is the case for instance when someone directly uses the git
repository without running setup.py.

Feature: advanced inc subtensor grad

More readable error when compilation fails

improved doc for R_op
it all looks good. There is one line that I think does not respect PEP8 convention but I'll fix it in another pull request