Font generator

Add webfont generator for koala, supported font type: ttf, otf, svg, woff, eot.
Node module ttf2eot [1] and fontforge [2] should be installed.
In Windows, it should configure fontforge path first. 
Not tested in Mac OS X.
[1] https://www.npmjs.org/package/ttf2eot
[2] http://fontforge.org