Merge pull request #4 from lmccart/master

pull from lmccart:master
preventDefualt on user input
adding noCanvas() method
fixing empty example
oops, forgot var in noCanvas()
Merge pull request #354 from shiffman/noCanvas

implemented noCanvas() as in issue #322
Context font is now updated whenever text properties are set.
Merge pull request #357 from scottgarner/master

Context font is now updated whenever text properties are set.
Merge pull request #352 from hrishit/master

preventDefault on use input
lib
adding support for p5.Element in child and parent closes #349
adding angleMode support to arc closes #348
adding link to dom tutorial for issue #346
adding doc for vid and audio file arrays for issue #346
Update core.js
adding hooks for preload screen issue #317, needs formatting and ability to subclass/modify before adding
Merge branch 'master' of github.com:lmccart/p5.js
Handle resize events and allow canvas resizing

* Added windowResized callback
* Made the createCanvas keep an id around so we can find user created canvases later
* Changed createCanvas to resize the graphics object if it already exists
* Added a resizeCanvas method
* Added resize to the p5.Graphics object
* (Minor) My editor stripped whitespace on some lines. It was only a small subset so I believe your standard is to strip them so I left it in.
loadXML reqwest fix: crossOrigin = true
save(p5.Graphics, filename) for consistency with other save argument signatures