Version 5.0.0

A major release, which aims at adapting the library according to the use of preferences in Android 8.0 and at fixing some fundamental issues. This required to re-implement large parts of the library:

• NavigationPreferences are now used as navigation items. This enables to use regular preferences and categories alongside with navigation items.
• Many methods and theme attributes have been renamed. However, most of the functionality of the previous versions is still available.
• Fixed situations where the state of fragments was not completely restored after orientation changes or after resuming the activity.
• Fixed a possible crash when using Android 7's multi-window mode on tablets.
• It is now possible to use the fullscreen layout instead of the split screen layout on tablets.
• The appearance pf dividers has been changed. They are now only displayed above a PreferenceCategory.
• Changed the activity's background color on phones.
• Changed the title text color of preferences and preference headers.
• Paddings and icon sizes are now equal for phones and tablet devices.
• Updated targetSdkVersion to API level 26 (Android 8.0).
• Updated dependency "AndroidUtil" to version 1.18.0.
• Updated AppCompat v7 support library to version 26.1.0.
• Updated CardView v7 support library to version 26.1.0.
• Updating the dependencies required to increase the minSdkVersion to API level 14.