Persistent signal market after scan + broadcast/amateur band markers

[gorucommit]

I modified the ats-mini firmware to display signal markings on the bottom tuning graph after performing a scan to make it easier to find stations & a permanent horizontal marker at the bottom for broadcast bands with red and amateur bands with blue. Packaged these in a separate UI Theme.

I find both features useful so I thought I'd share these as ideas for the main firmware...you guys can probably make something much better than me based on these.