replace if-else parameters verification with CV_Assert
remove dummy sepia test
add test for improper arguments in sepia function
correct coding style a little bit
edit sepia test to fix clang warnings
add macros to test if expected error is thrown
Merge pull request #33 from druzhkov-paul/sepia_asserts

change verification of parameters and mechanism of failures testing
Add matte implementation with sample and test.
Fixing problems and deficts.
Fixed code and make it a bit clear.