util.IntervalTimer (#2086) * Update util.lua - Added new function util.IntervalTimer, this is an IntervalTimer as found in the source SDK * Update util.lua * Update util.lua - Merged util.IntervalTimer with util.Timer * Update util.lua - Undo a change made to the util.Timer Started function * Update util.lua - Remove IsLessThan and IsGreaterThan functions from the util.Timer metatable * Update util.lua - Add missing comma * Update util.lua - Changed the return value of GetElaspedTime to -1.0 if the timer hasn't been started - Changed the util.Timer function to call the Start function upon creation * GetElaspedTime returns correct time after timer stops --------- Co-authored-by: Rubat <3299036+robotboy655@users.noreply.github.com>