Merge remote-tracking branch 'origin/2.4' into merge-2.4

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

cmake/OpenCVModule.cmake

@@ -303,7 +303,7 @@ macro(ocv_glob_modules)
   # collect modules
   set(OPENCV_INITIAL_PASS ON)
   foreach(__path ${ARGN})
-    ocv_get_real_path(__path "${__path}")
+    get_filename_component(__path "${__path}" ABSOLUTE)
 
     list(FIND __directories_observed "${__path}" __pathIdx)
     if(__pathIdx GREATER -1)
@@ -315,7 +315,7 @@ macro(ocv_glob_modules)
     if(__ocvmodules)
       list(SORT __ocvmodules)
       foreach(mod ${__ocvmodules})
-        ocv_get_real_path(__modpath "${__path}/${mod}")
+        get_filename_component(__modpath "${__path}/${mod}" ABSOLUTE)
         if(EXISTS "${__modpath}/CMakeLists.txt")
 
           list(FIND __directories_observed "${__modpath}" __pathIdx)