Merge 2.4 into master

Original pull requests:

* #1507 from pengx17:2.4_fix_test
* #1519 from ilya-lavrenov:ocl_minMax
* #1525 from asmorkalov:ocv_custom_libv4l
* #1530 from alalek:perf_tests_sanity_check_nothing
* #1532 from alalek:stereo_csbp
* #1533 from alalek:perf_test_update_relative_error_message
* #1535 from asmorkalov:android_ndk_r9
* #1542 from alalek:cl_runtime
* #1547 from SpecLad:gtest-1.7
* #1548 from ilya-lavrenov:ocl_bitwise_not
* #1549 from ilya-lavrenov:ocl_perf_norm
* #1555 from ilya-lavrenov:ocl_convertC3C4
* #1557 from ilya-lavrenov:ocl_minor_doc_update
* #1558 from SpecLad:Wparentheses-equality
* #1560 from jet47:cmake-config-cuda-5.5-fix
* #1561 from alalek:ocl_refactoring
* #1562 from ilya-lavrenov:ocl_integral
* #1563 from ilya-lavrenov:ocl_arithm
* #1564 from alalek:cl_runtime_fix_32bit
* #1566 from SpecLad:Wshadow-openni