Add basic framework to create guis

A JFrame that is a rootWindow contains a rootPanel that uses a
CardLayout. All the views of the storyboard can then be added to that
very rootPanel.
Refactor Game and Menu into its own Views
Refactor views to controllers
Add GameFieldView that paints the game field and a player square
Use Thread instead of Timer and maximize GameFieldView to Viewport
Refactor Main.java

The class now extends JFrame and simplifies much of its tasks.
Remove rootPanel creation

It is not necessary to create an extra content panel for the JFrame. Its
possible to just use the existing one and change its layout to
CardLayout.
Refactor view creation of controller into own method
GameField receives focus automatically when opening the gameview card
Refactor player into its own class
Refactor clearing and initializing of graphics into method
Add walls and floor to map
Change java version to inherit from eclipse settings
Recreate Thread for painting
Make initial coordinates of GameObjects dependent on GRID
Set size of content pane to respect window decorations
Add drawGrid() method which is called when drawGrid is true
Read rooms from files
Fix calculation issues with animation delay

A - B - C != A - (B - C) !!!
Add Start and Room symbols and change wall textures