media player : handle video filter's state properly
those changes provide an alternate/better way to handle video filter's state with a new object
this new object is available as a single instance accessor in the media player class and it encapsulate :
- all filter parameters' value, default value and allowed values range
- an accessor to enable/disable the filter
- an accessor to apply parameters from another filter
- an accessor to reset the parameters if needed
former filter accessors are using this new object and are still functional, but they should be avoided and are now marked as deprecated
This is a forward-port of !128 (merged) along with !133 (merged).