better ecma-48 detection in aixterm

found that the printable length of \x1b[32;4m was not detected by xterm
... why is that? because xterm's own would generate \x1b(B\x1b[32;4m.
Rather problematic, we use an ordered list to add this various alternate
types as a 'fall through', that is, at the end.
Merge branch 'ecma-48-sgr-aware'