[Lazarus] Universal FontDialog for LCL

[AlexeyT]

I have an idea to make LCL based TFontDialog- which will be LCL form, 
which can be called by TFontDialog.Execute (if Boolean variable in LCL 
is set). Why make it?

- we can make all best features of FontDlgs from all WSes

- we can make additional events- e,g, OnSelectFont (called when used 
selects name in listbox)

- we can make it resizable (and save/load size)

- same look on all WS

If it's good- ok to merge to Laz?

-- 
Regards,
Alexey