Normalizes Em references to Ember
Merge pull request #107 from jamesarosen/normalize-ember-references

Normalizes Em references to Ember
JSHint: ensure no use of undefined variables

 * Define runtime, buildtime, and spec globals
 * Define `version` in `buildSuite.js`, which didn't have a `var`
   due to a typo
Em -> Ember for consistency

 * No longer predefine `Em`
 * Use `Ember` everywhere for consistency
JSHint: ensure no unused variables
JSHint: require === and !==
Distinguish EmHandlebars from PlainHandlebars