[plot] set minimum marquee size

Users must draw a marquee box with diagonal size of atleast 7.5
pixels.  This prevents clicks from being translated to zooms on
the plot.  Because startMarquee triggers a plot history update.
endMarquee must remove the plot history update when preventing
marqueeZoom.  This has a side effect of causing a requery for
data, but is a simple enough solution for now.

Fixes #2002.

example/generator/StateGeneratorProvider.js

@@ -47,9 +47,7 @@ define([
 
         var interval = setInterval(function () {
             var now = Date.now();
-            var datum = pointForTimestamp(now, duration, domainObject.name);
-            datum.value += "";
-            callback(datum);
+            callback(pointForTimestamp(now, duration, domainObject.name));
         }, duration);
 
         return function () {

src/api/telemetry/TelemetryValueFormatter.js

@@ -57,8 +57,8 @@ define([
                 return vm;
             }, {byValue: {}, byString: {}});
             this.formatter.format = function (value) {
-                if (this.enumerations.byValue.hasOwnProperty(value)) {
-                    return this.enumerations.byValue[value];
+                if (typeof value === "number") {
+                    return this.enumerations.byValue[value] || value;
                 }
                 return value;
             }.bind(this);