Improved FreeSwipeScript and added Logger class

FreeSwipeScript :
The script now uses SwipRadius (float) and swipe.distance to adapt the
speed of the character.
If the swipe.distance > swipeRadius, hte script moves the start position
of the touch so the player won't have to move its finger back too far to
get to the opposite direction (ps : I know, i'm not clear :p). The
script displays an red circle to represent the start position of the
swipe and a full red disc to represent the actual position of the swipe.

Added Logger Class :
It contains the same methods as Debug* (* = Log, LogWarning,
LogException, LogError) but also posess a loglevel attributes to make it
only display the log inferior or equal to the current level :
Logger log = new Logger(2);
log.Log(1,"hello"); // Will be displayed
log.Log("5, "Test"); //won't be displayed