clarified variable names, removed magic number from discreteSteps

src/graph/Graph.js

@@ -22,7 +22,8 @@ function Graph (container, data, options) {
   this.renderRefreshRate = 60;                         // hz (fps)
   this.renderTimestep = 1000 / this.renderRefreshRate; // ms -- saves calculation later on
   this.renderTime = 0.5 * this.renderTimestep;         // measured time it takes to render a frame
-  this.maxRenderSteps = 3;                             // max amount of physics ticks per render step.
+  this.maxPhysicsTicksPerRender = 3;                   // max amount of physics ticks per render step.
+  this.physicsDiscreteStepsize = 0.65;                 // discrete stepsize of the simulation
 
   this.stabilize = true;  // stabilize before displaying the graph
   this.selectable = true;
@@ -1756,7 +1757,7 @@ Graph.prototype._isMoving = function(vmin) {
  * @private
  */
 Graph.prototype._discreteStepNodes = function() {
-  var interval = 0.65;
+  var interval = this.physicsDiscreteStepsize;
   var nodes = this.nodes;
   var nodeId;
 
@@ -1818,7 +1819,7 @@ Graph.prototype._animationStep = function() {
   var maxSteps = 1;
   this._physicsTick();
   var timeRequired = Date.now() - calculationTime;
-  while (timeRequired < (this.renderTimestep - this.renderTime) && maxSteps < this.maxRenderSteps) {
+  while (timeRequired < (this.renderTimestep - this.renderTime) && maxSteps < this.maxPhysicsTicksPerRender) {
     this._physicsTick();
     timeRequired = Date.now() - calculationTime;
     maxSteps++;