tests: cleanup, use error
ezplot: quiet tests when no codegen available

The workaround is fine here so its just noise.
sym will contain unicode pprint too

Should enable always unicode disp, eventually.
new display code, wip
disp: strtrimp(disp) -> x.flat change, most assumptions
new display code, part 2
octsympy_config: new display command, remove unicode command
display.m: clean up format strings
codegen: some disp(x) I changed before could also be a string, test fixes

New disp() means lots of strtrim(disp(x)) type code is broken, needs
to have disp(x,'flat') instead.