Basic code restructuring
Moved hook registration to seperate function
Moved constants to utilities class
Removed obsolete variable
Renamed variable
Added default value
Rewrote fileToMarkUp callback
Changed galley media processing
Removed int casts
Made variables references
Removed obsolete mime type detection function
Renamed variable
Remove comment
Added todo
Partial cleanup of html conversion method
Added todo
Gateway plugin basic cleanup
Switched to constant for plugin name
Added plugin name constant
Added plugin name constant