This benefits script authors and testers of ScriptFu.
Now a call to (display "foo") in a plugin goes to the terminal where GIMP started.
Whether interactive or in batch mode.
Make TS errors go to an error port instead of the output port.
Tool plugins: Console, Eval, Server get error messages from the error port.
TextConsole not changed. Tools behave per new doc "ScriptFu Tools" at dev web site.
Driveby fix of SF Server: send whole message instead of byte by byte.
Driveby comments and more semantic checking of set-output-port in TS.
Add test plugin test-display.scm
Move test plugins from /scripts to /scripts/test.
POTFILES.skip that directory.
Add a readme to scripts dir.
Revise readme in scripts/test
Rename test9.scm which tests the new byte type support in Scheme.
Install it in unstable build, it is an important test,
long and sophisticated.
Install contactsheet.scm as a test plugin in unstable build.
See test/meson.build for comments about its issue.
