Fix ideograph range check and a couple of resource leaks
Robert Sprowson authored
unicdata.c: condition changed to match unictype_is_ideograph() in UnicodeLib
keygen.c: free kb
keyconvert.c: free memory and close files on exit (the C environment would do this anyway, but this makes it explicit)
Picked up by static analysis
  https://www.riscosopen.org/forum/forums/4/topics/9503#posts-72623

Version 0.99. Tagged as 'IntKey-0_99'
887d9558