need terminal codes documentation

[najohnsn]

Interacting with a 3270 terminal (i.e. through zti) generally requires more than just the normal keys on a modern keyboard. But keys (and key combinations) outside of the normal keys are not consistently mapped by terminals used to run zti. The key codes that zti expects should be documented so that users can configure their terminal emulator to bind the appropriate codes key combinations.

For example:

Intended Key Combination	Expected Code(s)	Action
Shift+Enter	\n	newline
Alt+1	\0331	PA1
Alt+2	\0332	PA2
Alt+3	\0333	PA3
Alt+PgUp	\033\033[5~	Prev Session
Alt+PgDn	\033\033[6~	Next Session
Insert	\033[2~	Toggle mode

There are many others in addition to the ones in the table above. The codes can be determined from zti.py and _termlib.py.