Allow ids to contain hyphens. Fixes #36.

Previously, a mustache like {{foo-bar}} would generate a
parse error, which was a departure from the behavior of
other Mustache implementations.

lib/handlebars/vm.js

@@ -273,7 +273,7 @@ Handlebars.JavaScriptCompiler = function() {};
     // PUBLIC API: You can override these methods in a subclass to provide
     // alternative compiled forms for name lookup and buffering semantics
     nameLookup: function(parent, name, type) {
-      if(JavaScriptCompiler.RESERVED_WORDS[name]) {
+      if(JavaScriptCompiler.RESERVED_WORDS[name] || name.indexOf('-') !== -1) {
         return parent + "['" + name + "']";
       } else {
         return parent + "." + name;