This patch changes the way input characters are handled in function
terminal_process_char from big switch statement to smaller functions.
No functionality is changed in this patch.
Splitting to smaller functions will make easier to change behaviour
of terminal for prompt handling when user will be asked for something
and history substitution or auto completion will not be used.
Mostly indentation of arguments in functions and calls.
Prefix p remove from puser/penum_func.
Some empty lines added after closing } when needed.
Magic number for string length changed to preprocessor define.
Added spaces after casts.
This patch adds handling of Ctrl-C so it does not break tool.
To exit tool Ctrl-D is used on empty command line.
Ctrl-D on not empty command line works like Delete key.
