Should now automatically detect it during Android build

The version reported by toolchain is 4.6.x-google so regex needs an adjustment.

add OCL 1.2 feature for setTo
bug fix of integral
replace the error code -217 with suitable MACRO
simplify tests, no need apply a new context for each test case
add more control for tests in utility.hpp

added GPU non local means brute force filter + tests

To speed up rebuilds, define the NDK_CCACHE environment or CMake variable
to the path to your ccache binary. When declared, the android.cmake.toolchain
automatically uses CCache when compiling any C/C++ source file. For example:

export NDK_CCACHE=ccache

fixed MCVC warnings

added texture_binder

disabled -Wunused-but-set-variable because of multiple warnings during building nvcc auto generated files (GCC 4.6)