Added struct af_features to store image features (aka keypoints).
Added features class to manage af_features structs.
Added FAST feature detector frontend.
Added FAST feature detector CPU backend.
Added FAST feature detector CUDA backend.
Added FAST feature detector OpenCL backend.
Use & operator for array in resize definition
PERF: improvements to random number genration in CPU backend
Wrapping af_get functions in AF_CHECK macro
PERF: improvements to random number generation in CUDA backend
Fixes #167: Check if driver is unloaded when freeing array
Merge pull request #170 from umar456/devel

Fixes #167: Check if driver is unloaded when freeing array
Quote user-supplied paths. Search CMAKE_INSTALL_PREFIX last to prefer local installs.
Added handlers for array type in features class.
Fixed failing abs() call for int/unsigned types on CUDA backend of FAST.
Added test reader for image input with array output.
Added FAST unit tests.
PERF: improvements to random number generation in OpenCL backend

- Change incorrect macro check "T == double" to IS_DOUBLE
- Added try catch block around cl.hpp calls in random.hpp
- format changes to program.*
Merge remote-tracking branch 'upstream/devel' into fast
Merge pull request #173 from bkloppenborg/FindclFFTImprovements

Improve FindclFFT.cmake