[Limits] Add metadata to SWGs

Add telemetry metadata to Sine Wave Generators to support
utilizing telemetry in a 'datum' format, to match designed
API for WTD-1223.

example/generator/src/SinewaveLimitCapability.js

@@ -61,6 +61,7 @@ define(
                     return LIMITS;
                 },
                 evaluate: function (datum, range) {
+                    range = range || 'sin';
                     if (datum[range] > RED) {
                         return LIMITS.rh;
                     }