Prevent infinite loop if saving a URL and tapping "No Thanks"

Reproducible steps:

1) Open the iOS test app
2) Login to Pocket
3) Approve access for the app
4) Get redirected back to the iOS test app
5) In the browser, go to getpocket.com/connected_accounts and remove access for the iOS test app. Do NOT log out within the app.
6) In the IOS test app, tap a row to save it. It will redirect you to auth again.
7) Tap "No Thanks" and get redirected back to the test app

Prior to this commit, the test app would immediately try to log in again. Every time you tap "No thanks" it immediately attempts a new log in.

With this commit, the test app would not try to log in again, and will correctly report an error.
Updated SDK version to 1.0.1
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' of https://github.com/Pocket/Pocket-ObjC-SDK