RC : Allow user selectable StatusBar FontSize

PS 1: Combined the the FW side, this will allow the user to select
a custom font-size for text used on the StatusBar.
Note that I put this in 'Signal' area for now, but really needs to be on the
main preference screen as a sub-category of StatusBar (or in Gen UI?)
I didn't want to try and put in main area as no other preferences are set
directly there (all lead to other fragments).  But putting it in Signal
is misleading, as it effects other areas.  Putting in GenUI might be best,
but that area is already way too crowded.

ps 2:  Rebased and moved setting to GenUI.
ps 3: Fixed persistence of setting
ps 4:  Whitespace & Formatting.

Change-Id: Iadcecf66c23d98fca5557047eedf711e47b042dd
Signed-off-by: Zaphod <mwilson@acesappraisal.com>