Added permissions to retrieve Google Accounts: GET_ACCOUNTS, USE_CREDENTIALS & INTERNET
Replaced the mockup Accounts with real registered accounts
Updated SdkVersions (AccountManager supported only on API 5)
Removed redundant imports
Merge branch 'real_accounts'
Added mDisplayedAccount
Added the getAuthToken sample code
Gets the page of 'My Applications' and prints it to the log
Moved the authentication logic to GoogleAuthenticationActivity
Extracted authentication logic to AppEngineDashboardAuthenticator
Extracted getting the applications list to AppEngineDashboardClient
Deleted the model mockup classes
GoogleAuthenticationActivity calls the authentication method
Added the postAuthentication callback in the activity
Added debugging logs
Set GoogleAuthenticationActivity as the main activity and renamed MainActivity to DashboardActivity
AuthenticationActivity starts the DashboardActivity on success
Added the AppEngineDashboardAPI singleton
AuthenticationActivity uses the API
Removed the redundant getAccounts method