Do not purge ubuntuone-client-data

When purging it, ubuntu-desktop is also purged
Fix tag
libappindicator1 has been already installed
Install emacs-mozc whatever desktop environment is
Merge pull request #1 from itiut/trusty

Bump up to ubuntu 14.04
Merge branch 'master' into linuxbrew
Change ubuntu task to ubuntu role
Disable guest session on lightdm