Handlebars identifiers

Identifiers may be any unicode character except for the following which will fail validation:

Whitespace ! " # % & ' ( ) * + , . / ; < = > @ [ \ ] ^ ` { | } ~

• You may not include a closing bracket ] in a path-literal, but all other characters may be
  used.
• JavaScript-style strings and "double quotations" may also be used vs. [bracket pairs].
• To reference a property that is not a valid identifier, you can use segment-literal

  (bracket) [ ] notation {{#each articles.[10].[#comments]}}