Add new doodads:
* Start Flag: place this in a level to set the spawn point of the player
character. If no flag is found, the player spawns at 0,0 in the top
corner of the map. Only use one Start Flag per level, otherwise the
player will randomly spawn at one of them.
* Crumbly Floor: a solid floor that begins to shake and then fall apart
after a moment when a mobile character steps on it. The floor respawns
after 5 seconds.
* State Blocks: blue and orange blocks that toggle between solid and
pass-thru whenever a State Button is activated.
* State Button: a solid "ON/OFF" block that toggles State Blocks back
and forth when touched. Only activates if touched on the side or bottom;
acts as a solid floor when walked on from the top.
New features for doodad scripts:
* Actor scripts: call SetMobile(true) to mark an actor as a mobile mob
(i.e. player character or enemy). Other doodads can check if the actor
colliding with them IsMobile so they don't activate if placed too close
to other (non-mobile) doodads in a level. The Blue and Red Azulians
are the only mobile characters so far.
* Message.Broadcast allows sending a pub/sub message out to ALL doodads
in the level, instead of only to linked doodads as Message.Publish does.
This is used for the State Blocks to globally communicate on/off status
without needing to link them all together manually.
* Improve the collision detection algorithm so that Actor OnCollide
scripts get called more often WHILE an actor is moving, to prevent a
fast-moving actor from zipping right through the "solid" hitbox and
not giving the subject actor time to protest the movement.
* It's implemented by adding a `Settled` boolean to the OnCollide event
object. When the game is testing out movement, Settled=false to give
the actor a chance to say "I'm solid!" and have the moving party be
stopped early.
* After all this is done, for any pair of actors still with overlapping
hitboxes, OnCollide is called one last time with Settled=true. This is
when the actor should run its actions (like publishing messages to
other actors, changing state as in a trapdoor, etc.)
* The new collision detection algorithm works as follows:
* Stage 1 is the same as before, all mobile actors are moved and
tested against level geometry. They record their Original and New
position during this phase.
* Stage 2 is where we re-run that movement but ping actors being
intersected each step of the way. We trace the steps between
Original and New position, test OnCollide handler, and if it returns
false we move the mobile actor to the Last Good Position along the
trace.
* Stage 3 we run the final OnCollide(Settled=true) to let actors run
actions they wanted to for their collide handler, WITHOUT spamming
those actions during Stage 2.
* This should now allow for tweaking of gravity speed and player speed
without breaking all actor collision checking.
* Implement the pub/sub message passing system that lets the JavaScript
VM of one actor (say, a Button) send messages to other linked actors
in the level (say, an Electric Door)
* Buttons now emit a "power(true)" message while pressed and
"power(false)" when released. Sticky Buttons do not release and so do
not send the power(false) message.
* Electric Doors listen for the "power" event and open or close
themselves based on the boolean value received.
* If a Sticky Button receives power and is currently pressed down, it
will pop back up (reset to "off" position) and notify its linked
actors that they have lost power too. So if a Sticky Button held an
Electric Door open, and another Button powers the Sticky Button, it
would pop back up and also close the Electric Door.
