Fix EditTaskPanel validation problems

- Save enabled when comment is added
- Validation runs when Dates are changed
Fix exception caused by triggering save without changes
Merge branch 'develop' into bugFix-152-editing_validation

Conflicts:
	TaskManager/src/main/java/edu/wpi/cs/wpisuitetng/modules/taskmanager/view/tasks/EditTaskInformationPanel.java
	TaskManager/src/main/java/edu/wpi/cs/wpisuitetng/modules/taskmanager/view/tasks/tabs/TaskCommentPanel.java
Merge pull request #123 from R2-Team2/bugFix-152-editing_validation

Fix EditTaskPanel validation problems