new function setStyle on lime.Label

this enables setting of font style see the following issue
 https://github.com/digitalfruit/limejs/issues/79
forgot the function doc comments
Include font style for text measurement #81
Handle stroke size on text wrapping #81
Include font weight and font style on label demo #81
Merge branch 'label_style_render'
Update AUTHORS
Merge pull request #80 from MaliusArth/master

Enable appCache for non-webkit browsers