Started working on feature #162, some refactoring and preparations to drag multiple items.
Refactoring of addObject to parent to improve readability. Added SB error domain and specific error codes.
Feature working.
Refactoring: Divide and conquer, extract methods where comments were. Some renaming and removed my shortcut to open a specific project on startup.
Fixed: Moving nodes into themselves was possible if placed directly below under the selected node.
Refactoring: removed unused #imports. More extract method. Assert added for not supported index.
Refactoring acceptDrops outline method: extracted methods serving each case.
Fixed: Drag and dropping different resource types will disable dragging #297. Solution: prohibit dropping multiple types.
Bugfix for issue #46 Deleting folder with Interface files nested underneath, and then saving.
If a tab was open for a certain file and that file was deleted by deleting a parent folder the tab would be kept open. Saving now caused the crash since there was no valid currentDocument any more.
Solution: Close the tab as soon as a file gets deleted by deleted parents.
Ignoring CocoaPod files(future stuff) and AppCode project related files.
Bugfix: Caching is broken #294.
Fix is improving performance but is more like a quick solution than solving the underlying complexity problem.
Merge branch 'develop' of github.com:apportable/SpriteBuilder into develop-steffen

Conflicts:
	SpriteBuilder/SpriteBuilder.xcodeproj/project.pbxproj
Right click menu in resource view was limited to textures and folders only. Right clicking will highlight a row.
All resources can be deleted now with the right click option. Deletion works as follows: Right clicking will highlight a single item and delete it when it is outside a selected range of items. If the right click occurs outside a selction without a valid item the selection will be deleted. Behaves like in XCode's project navigator.
added sprite kit button/control plugin nodes
pbxproj update with button/control plugin nodes
Fixes custom properties
Merge pull request #316 from jtwigg/develop

Develop
Merge pull request #317 from jtwigg/develop

cocos2d upgrade.
Merge pull request #306 from NickyWeber/bugfix/issue_46_crash_del_folder_with_ccb_file

Bugfix for issue #46 Deleting folder with Interface files nested underneath, and then saving.
Merge pull request #311 from NickyWeber/bugfix/issue_294_caching_broken

Bugfix/issue 294 caching broken