Add Python 3 support to the Python test.py script.

The print function is used in place of the print statement.

The urlopen function has been moved to urllib.request in Python 3, so
attempt to import it from either location.

TestCase.assert_() has been deprecated in place of
TestCase.assertTrue().

The tests all pass in both Python 2 and 3.

Also, removed the one from modules/python/src2/cv.py and cleared its
executable bit, since it's not a script.

hopefully fixed handling of 'long' Python type in OpenCV bindings (bug #2193). added the corresponding test

Extended python bindings to support scalar values and tuples in place of InputArray (i.e. Mat) - ticket #2658. Added tests for #2611, #2505, #2658

Use github pat to get data for in python tests (files from code.opencv.org are received truncated sometimes)

updated some more links

updated links in cheatsheet
renamed directory for Mat tutorial 
changed links from willow docs to opencv.itseez.com, from Trac to current Redmine

disable implicit numpy array use in old-style Python bindings because of hard-to-fix memory leaks (ticket #1177)