Cancel pending auto-save if manual save occurs

Closes #4309
Peg ember-template-compiler to 1.7.0

Closes #4310
- Ember-template-compiler introduced a breaking change in
  1.9.0-alpha. We're using it via grunt-ember-templates.
Merge pull request #4313 from jaswilli/issue-4309

Cancel pending auto-save if manual save occurs.