* corrected and extended keyboard constants
* enabled checks against keyboard constants
* rTime is supposed to be a function that returns the current time in seconds (with the fractional part being the milliseconds)
* ReadTimerMS is supposed to also update the timer variable to the current time
* ReadTimerTick is supposed to return the number of milliseconds since the time value without modifying the timer
* change name of "Try" variable to "_Try" to keep Lazarus happy which doesn't comprehend that "Try" is not a keyword in TP mode... :/
* fix "a" to False as we currently don't have a "key is still down" detection
* use fully lowercase names