xsettings: use xsettingsd
xsettings: use a customized xsettingsd file
xsettings: use some helper to configure xsettingsd
redshift: fix location to Lausanne
terminal: use xfce4-terminal

While rxvt-unicode is great, it doesn't support xsettings making it
difficult to use when DPI can change while running.
terminal: fix xfce4-terminal invocation
xsettings: fix invocation of xsettings
terminal: use "terminal" for class

We do substring match. Dunno why "Xfce4-terminal" wasn't working...