Checks in order:

* first character comma? => first word is theme property name, rest value
  (open type-buffer with Esc, type ",typebufferfontsize 16" without the
  quotes, confirm.  see theme-files ("evidence.theme") for some example
  properties.  engine ("factory") names are not properties; they cannot
  be changed at run-time.)
  (",save" dumps the current properties to your evidence setup directory.)

* URL? => URL-handler from evidence.handlers (http://* goes to mozilla etc.)

* Dir? => evidence will show it.
  /foo/bar/baz works, /foo/bar/*.[ch] don't *yet*

* executable? => will execute it

* find a handler for the mime-type and start that with the file

* if all that fails, start as an executable with the parameters given,
  so "ls -Fls *.c" goes to the shell, and will output there as always.
