the location of the configuration directory now depends on how the
binary is built. release versions of the binary will look for the
gopher2600 directory in the user's os configuration directory.
non-release versions will look for the .gopher2600 directory in the CWD.
paths.ResourcePath() will create the paths that don't exist
paths.ResourcePath() now clearly differentiates paths and files
added build target to the Makefile; disabled release target for now
- removed ErrorID, using the error message as the ID
- works just as well and simplifies maintenance
- the messages should be moved to the relevant packages OR to a
locale package. not sure which yet.