extended the addPanel

We added dropdown menu and textfield next to the button
mainPanel

I put different font sizes and 3 different panels for categories in a
seperate file that is its own main class.
menu_bar

added a basic menu bar (file, edit, view)
Merge branch 'origin/Kim2'
Merge branch 'origin/master'
New Class
- TaskCategory : represents a category
- TaskItem : represent a task

Existing Class
- TimeManagerModel is now an Observable to be observed by the view
- TimeManagerView now implementats Observer
- TimeManagerMain has a dummy data initialization
- mainFram.setVisible() is temporarily moved to the main class because initialization of dummy data happnes there

New Methods
- TimeManagerModel:addNewTask()
- TimeManagerModel:addNewCategory() to be accessed by the controller
- TimeManagerView:update() to handle when the model data change, by calling 3 methods below:
- TimeManagerView:loadCategories() to load all categories
- TimeManagerView:loadTasks() to load all tasks
- TimeManagerView:removeAllTasks() to remove existing tasks
New Class
- TaskCategory : represents a category
- TaskItem : represent a task

Existing Class
- TimeManagerModel is now an Observable to be observed by the view
- TimeManagerView now implementats Observer
- TimeManagerMain has a dummy data initialization
- mainFram.setVisible() is temporarily moved to the main class because initialization of dummy data happnes there

New Methods
- TimeManagerModel:addNewTask()
- TimeManagerModel:addNewCategory() to be accessed by the controller
- TimeManagerView:update() to handle when the model data change, by calling 3 methods below:
- TimeManagerView:loadCategories() to load all categories
- TimeManagerView:loadTasks() to load all tasks
- TimeManagerView:removeAllTasks() to remove existing tasks