Set main window frame to auto save frame so that it will be restored on next run (in XIB file), Refactored pressedPanelVisibility: so that it would calculate and set the central panel frame once instead of twice during a call to the method, Also modified pressedPanelVisibility: so that it would always set the bottom panel visibility based on segment control, Used the modified pressedPanelVisibility: method to save panel states and to restore it on app start
Set main window central pane to remember splitter position across application restarts (via XIB file)
Save last open project info on SpriteBuilder termination and re-open project when next launched
Main window position saved, as well as the split views.
Split views: left panel first and second tab, and center panel between stage and timeline.
Preview view resized to fit upper split views view.
Storing and restoring of visible panels added. Thanks to FahimF.
Minor refactorings for readability.
Refactoring: Replaced string literals with constants for window state save and restore.
Registering userdefaults for window state.
Refactoring: Moved panel visibility code to MainWindow class.
MainWindow object added to MainMenu.xib referencing the AppDelegate's instance.
Rewired segmented control and panels to MainWindow instance in xib.
Code needed for debugging removed.
Bugfix: Modal sheets were malfunctioning.
Merge pull request #506 from NickyWeber/feature/#457_remember_window_state

Feature/#457 remember window state