Bugfix for https://github.com/spritebuilder/SpriteBuilder/issues/936.
Merge branch 'develop' into bugfix/#936_empty_package_names

Conflicts:
	SpriteBuilder/SpriteBuilder.xcodeproj/project.pbxproj
Merge pull request #1000 from NickyWeber/bugfix/#936_empty_package_names

Bugfix for #936 - Empty package names cause trouble