Refactored the API, moving it into a single api.js file which can be

exluded from a build if desired.

tasks/generate/js_api/templates/string.param.tmpl

@@ -0,0 +1,5 @@
+if (typeof <%= get %> !== 'object' && <%= get %>) {
+  <%= set %> = '' + <%= get %>;
+} else {
+  throw new TypeError('Invalid <%= name %>: ' + <%= get %> + ' should be a string.');
+}