PathConstrainer changes in JS Plugin + LinearConstrainer

PathConstrainer changes in JS Plugin + LinearConstrainer

Sample code showing how to use PathConstrainer in Javascript:

var pathConstrainer = new dali.PathConstrainer();
pathConstrainer.points = [ point0, point1, point2 ];
pathConstrainer.controlPoints = [ controlPoint0, controlPoint1, controlPoint2, controlPoint3 ];
pathConstrainer.forward = [1.0,0.0,0.0];

var constraintPosition = {
                          "target":actor,
                          "targetProperty":"position",
                          "source":actor,
                          "sourceProperty":"color-alpha",
                          "range":[0.0,1.0]
                         };

pathConstrainer.applyConstraint( constraintPosition );

Change-Id: If5c5aee0d402b5c689b983a9848648d6700dec6b