Fix release instructions

git push --tags pushes the tags only, not the commits.

Fixed error when cuda is not available

Minor typos

Fix for Python 2.4

Better exception handling

Fixes for Python 2.4

Using
    class X():
triggers a SyntaxError with Python 2.4

Infer shape

Implement tensor.sort(..., axis=None)

Sparse

Added tensor.sort() op

Sort2

Added missing tests for sparse op infer_shape op and replaced 2 tests that had error and implemetend them with DWF tests systems.