LibVrnaXXX as a class

I'm slowly getting acquainted with using classes in javascript.
Currently testing the encapsulation on v211 first, will do v185
later.

Example:

var vrna = new LibVrna211;

seq = 'CCCCGAAAGGGG';
var ret = vrna.fold( seq );
outln( seq );
outln( ret.mfe_structure );
outln( ret.free_energy );

delete vrna;