Simpler image creation using Image() object

See e.g. http://www.techrepublic.com/article/preloading-and-the-javascript-image-object/5214317
for more information
URI encode error message
Merge pull request #1 from kjbekkelund/image-object

Simpler image creation using Image() object
Merge pull request #3 from kjbekkelund/encode

URI encode error message
Encourage discussion
Merge branch 'master' of https://github.com/lillesand/js-onerror

Conflicts:
	public/index.html