* pass ModeDef pointer to mode_probe functions
* add extensions field to mode structure
* rename ascii mode to binary mode
* rename mode variables and fields to more specific names
added extensions .idl .json .pcc for c-mode
match perl scripts on #!.*bin/perl.*
added DisplayState.space_width
added do_electric_filename on minibuf_mode / and ~
expand ~ syntax upon completing filename entry in minibuf
enable undo in minibuffer