added line and error info to program line debug text

program model debugText() modified to output the line offset and size
before the line text and the error column, length and message after the
line text, but only if the new full info argument is true (the
equivalent of this code was moved from tester run() function)

modified tester encodeInput() to get error item (using new program model
access function) instead of getting the rpn list to check for an error