Help string in the sepia sample was modified.
Merge pull request #25 from valentina-kustikova/sepia_sample_fix

Help string in the sepia sample was modified.
New interface for glow function
Test implementation for glow filter
Edit glow implementation
Add glow sample
edit glow sample, edit CMakeLists
edit implementation
Fix glow test
Edit interface glow function, add exception handling, add new test for glow
Change interface glow function, create new sample
Correct interface of glow function