loadStrings fix

loadStrings was returning an empty array ('ret'), before the array gets
populated with strings. So I deleted 'return ret' and put the array
'ret' into the callback function once it's populated. Now it's working
for me, hopefully for others too!
Merge branch 'master' of github.com:therewasaguy/p5.js
merge pr
ran grunt, updating dist
fixing link to loop reference
fixing link to array access reference
adding createCanvas to API page
adding risdf13 examples 0-4
adding risdf13 examples 5-9
committing examples with tab spaces
cleaning up risdf13 examples so far
adding risdf13 examples 10-13
adding risdf13 examples 14-19
editing/adding instantiation examples
merging pimage
Merge branch 'master' of github.com:lmccart/p5.js
adding displayWidth and height and corresponding tests #106
fixing displaywidth better
Merge from master
Add support for PImage filters. The filters are structured in such a way that they should be usable outside of just PImage (for anything rendering a canvas).

Filters added include threshold, gray, invert, posterize and opaque.