added alias to config in app

and cleaned up code a bit.
fixed smaller issues in account template
reworked control flow in checkCredentialsAssistant

- if credentials are changed the encrypted stuff is modified
- and also the account.config object is updated
- the assistant now blocks until everything is done
- results are returned in all error cases
fixed some bugs in discoveryAssistant

code was not really tested before previous commit. ;)
changed oncreate assistant to call super function

Yeah... didn't know that this was possible. Now we let
the parent do its stuff and then add our own stuff.

Probably we'll need something similar for onEnable someday.
fixed nasty this issues in serviceAssistant
fixed some nasty bugs in accountConfigUtils.js
added ondeletassistant

this should delete account.config object.
It is not easy to test this, because it does not run
immideately. But now config object is gone from my
emulator's db. So I guess it worked.