Added GioRock to About and README

GioRock provided the Italian translation - many thanks!
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Add fancy font support for the new slider/text control
Finished* work on slider/text control

* I say "finished", but until I propagate the control throughout all of
PD, I won't know if it's actually "finished".  But testing on both an
integer (blacklight) and float (gamma) tool shows it to be working
marvelously, with much lower overhead than the previous version.
Convert "black light" tool to new slider/text control
Convert "gamma" tool to new slider/text control

This was the big one, as gamma requires double-precision correction and
synching across multiple values.  The new control shrunk the code
required by the tool in half!