Bugfix in Mame History lookup - delineation code was causing any multi-rom text to not display

However, multi-rom entries (info=outrun,outruna) still don't display the second or greater entry.
Went back to QP 3.8.4 and multiline entries against latest history.dat aren't working there at all either....
doc
History lookup now checks child if no parent found

Problem expressed in prior commit was found to be an error in mame history file with my test entry - outruna is now outrunra.
Meaning multiline lookups doubtless fine - I was seeing that MameUI is defaulting to searching for parent rom entry in cases where child isn't found.
Which is a good idea...
refactored half of history lookup into function call

because previous commit algorithm is incorrect - don't search for parent directly after child, if NO child is found in history dat, THEN search for parent
Next commit will complete that