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
playback/recorder and driven input systems moved out of the the ports
package and into a new input package. how the input systems interact has
been clarified and improved - for example, it is now posssible for a
playback file to be used to drive two emulations for comparison purposes
the debugger startup procedure has been clarified with two distinct
startup functions for playmode and debugger - each of which take
different arguments. the clarity has allowed the reintroduction of
recording and playback to the main play mode
