avoid 30 css links limit on MS internet-explorers

[dongyuwei]

IE loads only 30 css links, see http://blogs.msdn.com/b/ieinternals/archive/2011/05/14/10164546.aspx and the demo http://demos.telerik.com/testcases/BrokenTheme.aspx

My solution is slice the css links by 31, use a <style> tag to @import the 31 css files.

[j15e]

Unfortunately I do not think this should be dealt by sinatra-assetpack. It makes the core code quite tangled. But I am open to other cleaner solution like maybe creating a setting to use @import directives rather than styles for exemple.