Remove unused draw-bullets function

draw bullets functionality has been taken over by draw-list
Use a sprite batch to draw sprites
Add controls section to READE
comment out *show-fps* lines as it isn't in standard framework
Add player sprite to particle example

The error with sprite batch is evident here too, but
it manifest slightly differently, all the bullets save one
are covered with a player sprite
change to work with new vector2
remove particles example from branch in preperation for merge
Merge branch 'sprite-batch'

Conflicts:
	square-man.scm
fix merge mistake

I made a mistake during the merge
Fix seconds->ticks not renamed everywhere
Make bullets go up

when the direction of increasing y was changed bullets started going
down. This just made bullets go up again.
Make player movements in key-down easer to read
Enemies now follow the player

Add some basic functions to hopefully allow complex movement
Added functions v-, direction-to, velocity-towards, and follow
Change direction-to to use sprite positions
Remove move-left action
Basic orbit movement for enemies
Add functions for distance calculations

Use closer-than to check if an object is within a given distance
Rename functions consitently, move functions around
More complex moveent for enemies

Enemies approach the player then start to orbit around them,
At the moent the orbit is very jagged
Correct distance-square calculation