Improvements to the write answer feature:
* Hide the "......" prompt when write answer is off
* Show only the correct answer when nothing is typed, including in the write answer off case
* Show the correct answer normally instead of marked green when write answer is off.
* Add class typeOff when write answer is off, to allow hiding the correct answer via CSS.
Merge pull request #343 from ospalh/feature-type-answer-improvements

Improvements to the write answer feature