Added 'ClearHighlights' dispatch to scatter.

Created preliminary implementation of mousemove event on lineChart.

src/models/lineChart.js

@@ -147,9 +147,22 @@ nv.models.lineChart = function() {
       gEnter.append('g').attr('class', 'nv-y nv-axis');
       gEnter.append('g').attr('class', 'nv-linesWrap');
       gEnter.append('g').attr('class', 'nv-legendWrap');
+      gEnter.append('rect').attr('class', 'nv-mouseMoveLayer');
 
       //------------------------------------------------------------
 
+      wrap.select(".nv-mouseMoveLayer")
+      .attr("width",availableWidth)
+      .attr("height",availableHeight)
+      .attr("opacity", 0)
+      .on("mousemove",function() {
+          var padding = Math.floor(availableWidth / data[0].values.length);
+          var pointIndex = Math.floor(x.invert(d3.mouse(this)[0] + padding));
+          lines.dispatch.clearHighlights();
+          data.forEach(function(item, i) {
+              lines.dispatch.highlightPoint(i, pointIndex, true);
+          }); 
+      });
 
       //------------------------------------------------------------
       // Legend

src/models/scatter.js

@@ -34,7 +34,7 @@ nv.models.scatter = function() {
     , sizeDomain   = null // Override point size domain
     , sizeRange    = null
     , singlePoint  = false
-    , dispatch     = d3.dispatch('elementClick', 'elementMouseover', 'elementMouseout', 'highlightPoint')
+    , dispatch     = d3.dispatch('elementClick', 'elementMouseover', 'elementMouseout', 'highlightPoint', 'clearHighlights')
     , useVoronoi   = true
     ;
 
@@ -440,6 +440,10 @@ nv.models.scatter = function() {
   //============================================================
   // Event Handling/Dispatching (out of chart's scope)
   //------------------------------------------------------------
+  dispatch.on('clearHighlights', function() {
+      d3.selectAll(".nv-chart-" + id + " .nv-point.hover").classed("hover",false);
+  });
+
   dispatch.on('highlightPoint', function(seriesIndex, pointIndex, isHoverOver) {
       if (interactive) {
           d3.select(".nv-chart-" + id + " .nv-series-" + seriesIndex + " .nv-point-" + pointIndex)