Caching all fonts

[Nicola Pero]

I see we are now never releasing any NSFont object, but
caching/uniquing them using a global never-released dictionary.

Shall we discuss that a little ?

By just searching for a nice font in the Font Panel, I end easily up
creating more than 200 fonts.  Are we never going to release those ?
I will just use one or two of them in the real document.

By caching the 4 standard fonts (the ones returned by
boldSystemFontOfSize: 0 etc.) we already cache the fonts used in all
standard library widgets, so where is the advantage of saving all the
other fonts except wasting memory ?

Does it make the font panel faster ?  I couldn't notice any difference
between fonts already accessed and new fonts, but I am on a fast
machine.