Adapt ':char' command

- accept 0 (off) or 2..5 as number of characters before autosend starts
- changing input can be dropped with ESC
SPACE and DOWN no longer starts autosend feature
cleanup unneeded statements
implement reworked autosend feature

- starts after 2..5 characters
- shorter calls have to be finished with ENTER key
- as soon as autosend starts only alfanumerical keys are accepted
- no edit after input possible
- switch to sending exchange after 700 ms timeout
Allow autosend feature only in RUN mode
fix description of :CHAR in man page
rename to 'autosend' and comment funtion
Merge branch 'autosend'