Improve CourseNotFoundException throwing.

In ScheduleDetailListener, now search term and crn are passed along
with CourseNotFoundExcetion.
In ScheduleDetailTest, course not found messages now being printed to
stdout instead of stderr.
Rename HttpParseException and bug fix for ScheduleDetail.

Rename HttpParseException to HtmlParseException.
Fixed a bug when requestFinished flag not correctly set to true.
Bug fix for all parsers.

Fixed a bug when requestFinished flag not correctly to true after
request is finished or exception is thrown.