PEEK (2/2)

- Toggle PEEK On/Off
- Make PEEK and LN working togheter as different options
- Put a explanation abaout how these 2 fatures work together

Based on (with some modifications): https://github.com/AOSPA/android_packages_apps_Settings/commit/db85f442ab46ac74011a63f4fb5adc5c3c01df4f
Thanks  to: @BigBrother1984

Change-Id: I6c6c14f28336c959e739500fb2ffa6a45a60d963
Make spirit happen

Big thanks to Aries from Aries Droid Designs for those drawables

Change-Id: I0474c9bd97c4fa4a130fa2fa37b33358c5eede70