Change xmobar font (again)

A little experimentation showed that monospace-8 looks a lot better on
my Thinkpad X220.
Reformat the xmobar config file

It seems as if all of the xmobar configuraiton has to be inlined into
'Config' (e.g. no global variables), thus reindent the file to make
it more readable.
Change xmobar separator color
Solarize xmonad and xmobar colors
Change default terminal to urxvt