the logger.Permission interface indicates whether the environment making
the logging request is allowed to create new log entries. the
environment.Environment type satisifies the Permission interface
logger.Allow is provided as a convienient way of indicating the the log
entry should always be created
float32 pair defined as ports.EventDataPaddle
added functions to convert the float32 to and from a playback entry.
conversion from the playback entry tolerates a single float32 value
meaning that old recording files will work
rename plugging.PortLeftPlayer and plugging.PortRightPlayer to just
plugging.PortLeft and plugging.PortRight
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
