This patch causes the tape load trap code to set
various Z80 registers more or less in accordance with
the behaviour exhibited by a real Spectrum, or at least
FUSE when told to not use tape traps.
Some simplifications have been made to account for the
fact that some load errors simply don't happen (e.g.
there are no incomplete bytes in TAP files or in TZX
Some testing is still needed :-)
The DE=0 patch (1.113->1.114) must be reverted before
application of this patch.