recreator: added colon support

added a check for the colon sub-code to the main recreator loop, which
adds a colon and a space to the output when set in the token just
processed

added a check in the rem recreate function to not add a space before the
rem operator if the last character in the output string is a space;
added a last access function to recreator class to return the last
character in the output string or a null character if the output string
is empty

the expected recreated output files for translator test 16 (colon tests)
were updated to the expected recreated outputs (all statements are
recreated correctly)