Merge 2.4 into master

Original pull requests:

* #1623 from ImAlsoGreg:2.4-pkgconfig-dash-l
* #1643 from alalek:cmake_fix_java_link_rules
* #1649 from asandwhich:2.4
* #1655 from pengx17:2.4_opt_superres_ocl
* #1658 from alalek:ocl_fixes
* #1659 from ilya-lavrenov:ocl_examples
* #1666 from SpecLad:cv-cap-openni
* #1667 from SpecLad:detect-openmp
* #1669 from ilya-lavrenov:ocl_copyMakeBorder
* #1672 from ilya-lavrenov:ocl_arithm
* #1673 from ilya-lavrenov:ocl_norm
* #1674 from alalek:cmake_fix
* #1676 from ilya-lavrenov:ocl_resize_test
* #1678 from wejeus:ios-documentationfix-2.4
* #1679 from ilya-lavrenov:ocl_equalizeHist
* #1680 from alalek:cmake_fix_android_builds
* #1682 from SpecLad:Wmissing-declarations
* #1683 from alalek:ocl_restore_showdiff
* #1689 from ilya-lavrenov:ocl_bilateralFilter
* #1690 from SpecLad:cmake-2.8.12
* #1692 from ilya-lavrenov:ocl_separableFilter
* #1693 from ilya-lavrenov:ocl_adaptiveBilateralFilter
* #1694 from apavlenko:fix_typo
* #1697 from SpecLad:sdk-redux