add exception handling

MismatchedCommandException in taskManager methods.
add priority to Task
improve test for Task
add logging to Controller
add .log files to gitignore
Merge branch 'master' into sun-defcoding
getTasks for UI
Add Controller.getTasks() so data will be populated in the ListView
Merge remote-tracking branch 'origin/tys-ui' into sun-defcoding

Conflicts:
	src/application/Controller.java
merged with SUN BRANCH Controller.GetTasks()
resolving conflict
Merge branch 'sun-defcoding' into tys-ui