Merged pull requests:
#890 from caorong:patch-1
#893 from jet47:gpu-arm-fixes
#933 from pengx17:2.4_macfix_cont
#935 from pengx17:2.4_filter2d_fix
#936 from bitwangyaoyao:2.4_perf
#937 from bitwangyaoyao:2.4_fixPyrLK
#938 from pengx17:2.4_surf_sample
#939 from pengx17:2.4_getDevice
#940 from SpecLad:autolock
#941 from apavlenko:signed_char
#946 from bitwangyaoyao:2.4_samples2
#947 from jet47:fix-gpu-arm-build
#948 from jet47:cuda-5.5-support
#952 from SpecLad:jepg
#953 from jet47:fix-bug-3069
#955 from SpecLad:symlink
#957 from pengx17:2.4_fix_corner_detector
#959 from SpecLad:qt4-build
#960 from SpecLad:extra-modules
Conflicts:
modules/core/include/opencv2/core/core.hpp
modules/gpu/CMakeLists.txt
modules/gpu/include/opencv2/gpu/device/vec_math.hpp
modules/gpu/perf/perf_video.cpp
modules/gpuimgproc/src/cuda/hough.cu
modules/ocl/include/opencv2/ocl/ocl.hpp
modules/ocl/src/pyrlk.cpp
samples/gpu/driver_api_multi.cpp
samples/gpu/driver_api_stereo_multi.cpp
samples/ocl/surf_matcher.cpp
The new sample adjust some parameters thus it should always be able to
calculate valid homography matrix when input is box.png and
box_in_scene.png.
Pure cpp surf and bfmatcher implementation is also added to show the user
its accuracy and performance.
