and the magic fixup of opening parentheses.
This commit moves the automatic insertion of matching parens to the
scheme mode keymap, so it will now take affect in Racket mode editing,
only. Also, Rackety.
this meant that if some line were supposed to be indented in the third
column and you had two tabs and a space on that line, the indenter
would leave it alone. Now, if it sees tabs in the line anywhere, it just
decides that the line is not properly indented and re-indents it
(always using spaces)
Also: started a tabber test suite
