Add child accessor API

lib/handlebars/compiler/compiler.js

@@ -453,10 +453,17 @@ export function compile(input, options, env) {
   }
 
   // Template is only compiled on first use and cached after that point.
-  return function(context, options) {
+  var ret = function(context, options) {
     if (!compiled) {
       compiled = compileInput();
     }
     return compiled.call(this, context, options);
   };
+  ret.child = function(i) {
+    if (!compiled) {
+      compiled = compileInput();
+    }
+    return compiled.child(i);
+  };
+  return ret;
 }

lib/handlebars/runtime.js

@@ -97,7 +97,7 @@ export function template(templateSpec, env) {
     compilerInfo: templateSpec.compiler
   };
 
-  return function(context, options) {
+  var ret = function(context, options) {
     options = options || {};
     var namespace = options.partial ? options : env,
         helpers,
@@ -119,6 +119,11 @@ export function template(templateSpec, env) {
     }
     return templateSpec.main.call(container, context, helpers, partials, data);
   };
+
+  ret.child = function(i) {
+    return container.programWithDepth(i);
+  };
+  return ret;
 }
 
 export function programWithDepth(i, data /*, $depth */) {