Refactored initialization of browsing root states to new classes (MP2-377)
Added MovieAspect/SeriesAspect to MediaLibraryBrowsing, allows use of fanart in browsing mode (MP2-377)
Use layout settings from media browsing root state for all sub screens. Layout changes only work from current to all further screens (MP2-377)
Avoid saving changes when constructing new instances (MP2-377)