added lexer/parser support for templated metric expressions, karma test runner is working

tasks/options/karma.js

@@ -0,0 +1,9 @@
+module.exports = function(config) {
+  return {
+    unit: {
+      configFile: 'src/test/karma.conf.js',
+      singleRun: false,
+      browsers: ['Chrome']
+    }
+  };
+};