v1.5.4 QoL updates

QoL fixes

No longer need to special case $player with $global: true
Stdlib: adds Number#round_to_nearest
^i{} initializer now implemented wrapped as immediate function
Adds RezDie#open_roll
Calling event handlers converts false into RezEvent.noop()
Adds events to RezGame for scene/end, scene/pause, and scene/resume
All Rez CSS classes now have a "rez-" prefix
Adds missing accessors