fixed change user function

it is kind of working, although you wont actually be able to select an new youtube account
as long as you are still logged into the same google account and or you did not revoke the
access token to this app
removed "authuser" parameter in "gapi.auth.authorize"

the "authuser" parameter is not even documented, but setting it to -1 seems
to force a selection popup for your google account, still not what i want
removed all references to old localstorage

i wont bother with migrating old data, but i might switch to a
different storage than local storage in the future, so i am
keeping localforage
css file formatted
removed setting of apiKey

because:
1) it is set in the GoogleApiProvider
2) the source of this assignment is undefined
fixed video list

ng-repeat had problems duplicate videos in the list, at first glance their where not any
duplicate videos, anyways i switched item tracking to index
handling for multiple youtube accounts

first steps towards support for multiple youtube accounts, also immediate auth is working
changed warning messages

removed the warning message in grid view, instead a new warning on the frontpage is shown