critical.js beta 4

I updated critical.js to be beta 4, from beta 3. The library is rather restructured now. The biggest change is moving from modifying host objects to using the crit namespace. As a result, it now type-checks the inputs, because it can no longer be positive that print is being used on an Array object. I also used JSDoc syntax for comments in the full source. A full list of changes is as follows:

• Moved all methods to crit namespace
• Add clone function, to clone an object
• Modified allBut to work on strings
• Redid map to be simpler for me to understand
• Merged count, nthIndexOf, and scramble into a single function for arrays and strings
• Added support for start parameter to nthIndexOf
• scramble for arrays no longer modifies the source array
• Changed Array.random to crit.arandom
• Changed Array.print to crit.aprint
• Changed String.reverse to crit.sreverse
• Changed String.repeat to crit.srepeat
• Changed String.trim to crit.strim
• Changed Boolean.toBin to crit.btoBin
• Allow btoBin to be used on any object type parsable as a Boolean

Please try it out and report bugs!