bugfixes
two types of events - system and user. system events are cleared and not
recorded
events run on delta time instead of absolute time now. Makes it easier
to move events from one recording to another or compose tests.
Togglebutton style was incorrect for controls
event arg value return was independent of arg type - leading to
underflow exceptions. now returns sensibly but does not coerce yet.
field arrow when too small was causing problem with drawing circle.