- set init value for `numsdev` to prevent use of uninitialized value
- stop use of 'workdir' and files from samples
- forcing use of 'opencv_extra' instead
Note: set OPENCV_TEST_DATA_PATH to full path to 'opencv_extra/testdata' (gitolite@code.opencv.org:opencv_extra.git) before running the test!

Downgrade TBB to 4.1u2 for all platforms, except WinRT.

Fixed issue 3130 (http://code.opencv.org/issues/3130), where one argument of the BRISK-call was ignored. Previously it was not possible to use BRISK without creating descriptors.
Now it behaves like ORB (and how it is documented), and you can call BRISK to just generate feature points and no descriptors.

Example: img of size 10x10 and templ of size 11x9.
In subsequent code this will results in either width or height of
corrSize to be zero (0).
Line 261 will call crossCorr which will then have a zero size of either
blocksize.width or blocksize.height resulting in a division by zero
crach in lines 137 or 138.

[NSRunLoop currentRunLoop] is not the same as in the main thread.
see
https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/F
oundation/Classes/nsrunloop_Class/Reference/Reference.html
"If no input sources or timers are attached to the run loop, this
method exits immediately"

The old code caused grabFrame() to return immediately if the capture
was not done in the main thread.
This code works correctly, even in secondary threads, provided that all
capture functions are called in the *same* thread