Additional notes with this commit:
1. Add cornerHarris_dxdy and cornerMinEigenVal_dxdy to get
the interim dx and dy output of Sobel operator;
2. Add minMax_buf to allow user to reuse buffers in minMax;
3. Fix an error when either min or max pointer fed into minMax is NULL;
4. Corner sorter temporarily uses C++ STL's quick sort. A parallel
 selection sort in OpneCL is contained in the implementation but disabled
due to poor performance at the moment.
5. Accuracy test for ocl gfft.

We found that cl.h file provided in latest Intel SDK muted deprecated interfaces.

Add backwards portability for OpenCL 1.1 when OpenCV executables
are compiled with OpenCL 1.2 profile support.

1. Added more sync to reduction.
2. Turned off Image2D feature. Probably its support is not detected correctly.
3. Temporary disabled descriptor tests - can't localize a problem of the ocl descriptor.

remove as much warnings as possible
use enum instead of MACRO for ocl.hpp
add command line parser in accuracy test and perf test
some bug fix for arthim functions

change the download channels to oclchannles()
fix bugs of arithm functions
perf fix of bilateral
bug fix of split test case
add build_warps functions