SPA: remove the signin and signout API

Bubbles up the API to the generic SPA interface.
Increase the timeout for switch to frame to avoid intermittent failures on travis
SPA: add the setCredential method

setCredential send the credential to the SPA subworker.
It should be called before connect or autoconnect.
Extend long polling timeout for tests to avoid timeouts during travis runs due to slow running Firefox.
Update incoming call text. r=@dmose over irc
Merge pull request #266 from Standard8/long_polling_timeout

Extend long polling timeout for tests to avoid timeouts during travis runs due to slow running Firefox.
Add a comment to explain the extended timeout
Merge pull request #265 from Standard8/sidebar_inter_fail

Increase the timeout for switch to frame to avoid intermittent failures on travis
SPA: merge setCredentials, connect and autoconnect
Change 'to' to 'peer' in the SPA interface to make it consistent with the rest of the interface and the code.
HTTP: improve the error callbacks
SPA: implement reauth-needed.
Frontend tests: include a missing file
Add tests for reauth-needed.
Fix jshint error
Merge pull request #267 from Standard8/spa_use_peer

Change 'to' to 'peer' in the SPA interface to make it consistent with the rest of the interface and the code.
Fix old autologin
SPA: improve test coverage
Merge branch 'master' into spa-connect-interface
Fix minor typo