Made changes so that TaskerLog does not produce logged outputs to console. Only to file.
Merge branch 'master' of https://github.com/cs2103aug2014-T13-2J/main

# By mervynwee
# Via mervynwee
* 'master' of https://github.com/cs2103aug2014-T13-2J/main:
  Remove FIELD_COMPLETED and add FIELD_COMPLETE and FIELD_INCOMPLETE so that updateHandler can cater to the complete and incomplete task cases. Remove updateCompleted function since it was originally used by FIELD_COMPLETED. Create and fully implement updateHandlerTest.java to test updateHandler class.