Fixed number precision when draggableRange=true

When there was set options.precision>0 (non-zero fraction part)
and moved a range there was a issue with number rounding on both
ends of selected range. Sometimes numbers had small value at far fraction.

It can be reproduced with live demo by setting, for example:
  minValue: 3.6,
  maxValue: 5.8
  floor: 0,
  ceil: 10
  step: 0.1,
  precision: 1,
  draggableRange: true

It's possible to produce value, e.g: 6.2999999999... but used precision
expects to see rounded value: 6.3.

Author: radomik

dist/rzslider.css

@@ -1,7 +1,7 @@
 /*! angularjs-slider - v2.9.0 - 
  (c) Rafal Zajac <rzajac@gmail.com>, Valentin Hervieu <valentin@hervieu.me>, Jussi Saarivirta <jusasi@gmail.com>, Angelin Sirbu <angelin.sirbu@gmail.com> - 
  https://github.com/angular-slider/angularjs-slider - 
- 2016-02-18 */
+ 2016-02-24 */
 rzslider {
   position: relative;
   display: inline-block;

dist/rzslider.js

@@ -1,7 +1,7 @@
 /*! angularjs-slider - v2.9.0 - 
  (c) Rafal Zajac <rzajac@gmail.com>, Valentin Hervieu <valentin@hervieu.me>, Jussi Saarivirta <jusasi@gmail.com>, Angelin Sirbu <angelin.sirbu@gmail.com> - 
  https://github.com/angular-slider/angularjs-slider - 
- 2016-02-18 */
+ 2016-02-24 */
 /*jslint unparam: true */
 /*global angular: false, console: false, define, module */
 (function(root, factory) {
@@ -1549,15 +1549,18 @@
             return;
           newMinValue = this.minValue;
           newMaxValue = this.minValue + this.dragging.difference;
+          newMaxValue = this.roundStep(newMaxValue);
         } else if (newOffset >= this.maxPos - this.dragging.highLimit) {
           if (this.maxH.rzsp === this.maxPos)
             return;
           newMaxValue = this.maxValue;
           newMinValue = this.maxValue - this.dragging.difference;
+          newMinValue = this.roundStep(newMinValue);
         } else {
           newMinValue = this.offsetToValue(newOffset - this.dragging.lowLimit);
           newMinValue = this.roundStep(newMinValue);
           newMaxValue = newMinValue + this.dragging.difference;
+          newMaxValue = this.roundStep(newMaxValue);
         }
 
         this.positionTrackingBar(newMinValue, newMaxValue);

dist/rzslider.min.css

@@ -1553,15 +1553,18 @@
             return;
           newMinValue = this.minValue;
           newMaxValue = this.minValue + this.dragging.difference;
+          newMaxValue = this.roundStep(newMaxValue);
         } else if (newOffset >= this.maxPos - this.dragging.highLimit) {
           if (this.maxH.rzsp === this.maxPos)
             return;
           newMaxValue = this.maxValue;
           newMinValue = this.maxValue - this.dragging.difference;
+          newMinValue = this.roundStep(newMinValue);
         } else {
           newMinValue = this.offsetToValue(newOffset - this.dragging.lowLimit);
           newMinValue = this.roundStep(newMinValue);
           newMaxValue = newMinValue + this.dragging.difference;
+          newMaxValue = this.roundStep(newMaxValue);
         }
 
         this.positionTrackingBar(newMinValue, newMaxValue);