function unbind( evt, namespace, callback ) {
		var bound = this.shoestringData.events[ evt ];
		if( !(bound && bound.length) ) {
			return;
		}

		var matched = [], j, jl;
		for( j = 0, jl = bound.length; j < jl; j++ ) {
			if( !namespace || namespace === bound[ j ].namespace ) {
				if( callback === undefined || callback === bound[ j ].originalCallback ) {
					this.removeEventListener( evt, bound[ j ].callback, false );
					matched.push( j );
				}
			}
		}

		for( j = 0, jl = matched.length; j < jl; j++ ) {
			this.shoestringData.events[ evt ].splice( j, 1 );
		}
	}
Unbind a previous bound callback for an event.

@param {string} event The event(s) the callback was bound to..
@param {function} callback Callback to unbind.
@return shoestring
@this shoestring