Mat tutorial - grammar and spelling fixes
simplify the kernel logic when using rect kernel or without ROI
enable Tegra optimizations
matchTemplate perf tests added
blend use vector to optimize
Make parallel video writer test pass if compiled without threading support
stricter eps for normed methods
onCameraFrame callback signature changed. CvCameraFame interface added.

New interface allows to get one RGBA or Gray frame from camera or both in the same time;
New interface fixes data rase in samples also.
Android samples updated according onCameraFrame callback signature change.
FpsMeter class removed from Image Manipulations and Face Detection examples as unused code.
remove a warning on Linux
fix a error in doc
Merge pull request #431 from snosov1:matchTemplate-tegra
Merge pull request #432 from bitwangyaoyao:2.4_blend
remove the warnings in accuracy test
Merge pull request #438 from bitwangyaoyao:2.4_fixwarings
Merge pull request #434 from taka-no-me:fix_parallel_writer_test
added 8u type support to filterSpeckles function
Video IO perf tests guarded.
TBB download and build option enabled for non Android platfroms.
Cross compilation toolchain for arm linux added.
TBB build defines for Linux added.