add documentation for glow function
fix list
fix error with equation
fix list
add default value for sigma
Images to the sepia documentation were appended.
Merge pull request #44 from valentina-kustikova/sepia_docs_fix

Add images to Sepia documentation
Merge pull request #36 from stragger/glow_documentation

Add documentation for Glow function
Clean repo
change algorithm description in Tint filter docs. rename images.
merge with master