Use RubyBBCode as module name

Same as the rest of the code uses
Fix rdoc generation
Remove deprecated method
Start method names in String class with 'bbcode'

This makes it (more) clear where the method comes from.
Any of our public methods (outside RubyBBCode namespace) should start with bbcode for this reason
Version number got accidentally updated by f2b925eac38c2f00176a24209ad2b228df9543ec