apart from better organisation, these changes fix a bug in CDF that
could cause a crash caused by the ARM program accessing a memory address
that is not represented in the emulation
curated package predated the standard errors package introduced in
go1.13
the standard package does a better job of what curated attempted to do
the change of package also gave me a opportunity to clean up the error
messages a little bit
identified the functions in the debugger package that are used by the
lazyvalues package. it is planned that the lazyvalues system will be
replaced by a Borrow() mechanism so this is a change with a limited life
expectancy
