Added use of synapse PPA to installer. This is because synapse was removed
from ubuntu 14.04.
It seems that in the version of xmobar in Trusty, the -c option
to the battery module is no longer supported. But it seems to work
just fine without it!
Fixed issue where xmobar couldn't find the volume display script.

Apparently xmobar no longer expands tilde to the home directory,
so you now have to pass the script as an argument to bash.
Updated README for Ubuntu 14.04.