Fixed a bug where installing multiple Mac apps with the Pocket SDK would cause keychain keys to be in conflict

Steps to reproduce:
1. Install a 3rd-party app with the Pocket SDK
2. Login
3. Build and run the test app under the Release configuration
4. The app should not be logged in, try to access other keychain items, or return a 137 error from the Pocket API
Updated to 1.0.2
Added migration for Mac 1.0.2 SDK
Fix issue where user-agent was not being populated fully
Merge branch 'master' into cocoapods-dependency