removed ffmpeg dependency from gpucodec module:

used implementation from highgui module
bugfix #3121: corrected calculation of blue channel index
trajectory with spheres and lines (based on the code snippet in gdocs)
adding/tuning multiple run for perf tests failing due to big deviation (functions using TBB can work so)
fixed Bug #3143 - flann 'not implemented' error
cloud collection widget implementation
fix cap_qtkit.mm for multithreaded applications

cap_qtkit does not work when the capture is run outside of the main
thread.
If the capture is launched in a separate thread, then [NSRunLoop
currentRunLoop] is not the same as in the main thread, and has no timer.
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"

Using usleep() (which I previously proposed, and was reverted) is not a
good alternative, because it may block the GUI.

Here is the new proposed solution:
- create a dummy timer so that runUntilDate does not exit immediately
- simplify the loop by using runUntilDate instead of runMode:beforeDate
- fix potential memory leaks (pointed out by Xcode's static analysis)
- fix init to follow Objective-C guidelines
- fax warnings about conversions from size_t to int
fix signedness error

OpenCV's automatic builds don't care if you store an unsigned int into
an int, but they don't want you to compare signed with unsigned. Does
that make sense?
Changed cornerHarris description to say it finds corners, not edges
New intersection function for rotated rectangles
Fixed ret
changed from isnormal to isfinite, the prev ignored zero
Added gittip button
Rename README to README.md
Update README.md
Update README.md
Added C interface
Documentation fix for cv::compare (issue 3149)

Since commit d8417af0860 (July 2011) cv::compare produces an array with
the same size and type as the input arrays.

Signed-off-by: Michael Hanselmann <public@hansmi.ch>
fix: trajectory path is now relative to the global frame
added add_definitions(-DCVAPI_EXPORTS) to cmakelists.txt