Enhanced debug

Created by: bbert

This PR enables to extend debug log messages with callee class name, and media type if available. This may facilitate debugging by filtering log messages in the browser console.

For example, if you filter log message related to DashHandler for video track, then you would get the following messages to displayed:

By the default, class names and types are not displayed. This can be enabled by calling

player.getDebug().setCalleeNameVisible(true);