implement first stages of active mode communication

htdocs/lib/Modes.js

@@ -0,0 +1,28 @@
+var Modes = {
+    modes: [],
+    features: {},
+    setModes:function(json){
+        this.modes = json.map(function(m){ return new Mode(m); });
+    },
+    setFeatures:function(features){
+        this.features = features;
+    },
+    findByModulation:function(modulation){
+        matches = this.modes.filter(function(m) { return m.modulation === modulation; });
+        if (matches.length) return matches[0]
+    }
+}
+
+var Mode = function(json){
+    this.modulation = json.modulation;
+    this.name = json.name;
+    this.requirements = json.requirements;
+};
+
+Mode.prototype.isAvailable = function(){
+    return this.requirements.map(function(r){
+        return Modes.features[r];
+    }).reduce(function(a, b){
+        return a && b;
+    }, true);
+}