add dat.gui.js
add variables control panel for width and height of canvas
Merge pull request #56 from victorleungtw/master

add variables control panel
add grunt as a devDependency
Merge pull request #57 from mcpike/master

add grunt as a devDependency
add Grntfile.js
add grunt uglify to devDependencies
Merge pull request #58 from mcpike/master

add Gruntfile.js
center visual effects