Hotfix: 1.7.1

Issue tracker for 1.7.1

- [x] Add deactivation option for the Github updater class.
- [x] Fix an early API request that asks for themes before the user has entered their credentials.
- [ ] Theme Update Option Not Available #41
- [ ] Declaration of Envato_WordPress_Theme_Upgrader #38
- [ ] Assigning the return value of new by reference is deprecated #37
- [ ] doesn't appear on dashboard sidebar #36 & envato-wordpress-toolkit activated but doesn't appear in sidebar #29
- [ ] Doesn't Work Any Longer #35