added new pin modifiers to from_string...
 ! = invert pin
 o = set pin to open drain
 ^ = set pin to pull up
 v = set pin to pull down
Set no pullup the default for open drain outputs
added repeater mode
added - to set no pullup
added @ to set repeater mode
Pin::from_string: change nested loops for condition in case default to allow & ignore whitespace
Robot & Extruder: enable pins are no longer open drain. If you need open drain enables, put an 'o' after the pindef in your config ala Jim Morris' recent 947ae5 commit
strip utf8 nbsp from comments