Adding rectangle object
updated circletest and polygontest to fix urls and rendering errors for root polygon element, added polygon.default_path() to easily recompute path for default shape (equilateral triangle)
merged from issue 8 branch, automerge failed
fixed unresolved conflicts that were added accidentally on last commit
refactored dronewar ship bullet parameters into ship module and cleaned up dronewar root element, fixed some bugs in menu
tweaked dronewar and animation speed parameters based on gameplay testing using a core 2 duo laptop with 4GB RAM
updated dronewar parameters to make it more closely resemble the original version published on gameprez.com about a week ago
fixed a bug in polygontest (bullets destroying root) and tweaked initial spacing of circles and polygons in circletest and polygontest to reduce number of objects in contact at t=0 to avoid triggering too many transitions simultaneously on first contact
adjusted initial position of bullets fired from ship in dronewar
recompiled and zipped dronewar
added dynamic quadtick calculation and fixed a bug in circletest where bullet destroyed root element
changed quadtree delay to avoid using _.min, assuming 1 ms per element update for simplicity
Merge branch 'dev' of https://github.com/gameprez/gpdk into enhancement-#3-retangle-element

Need to update to the resent changes.
updating branch to latest changes
added rectangle.coffe to changes from dev merge
impelemented a global Collision.use_bb switch to treat all elements as rectangles, instead of a separate Rectangle element. updated collision and game code to check for use_bb switch. renamed death to destroy. renamed pathwidth and pathheight to bb_width and bb_height and added a BB() method to element class and its descendents. updated polygon and collision to use BB where appropriate
recompiled and zipped dronewar