Extract notifications settings.
Move and rearrange some settings.
Show notifications for every show by default.
Create UpdateSettings, move relevant settings there.

- Also create and use settings helper methods.
Create DisplaySettings, move relevant settings there.

- Also created helper methods to get those settings and using them
everywhere.
- Also moved some helper methods directly into the settings class.
Move some pure activity related settings back to ActivitySettings.

- DisplaySettings was getting crowded.
Create TraktSettings, move related settings there, add helpers.
Move GetGlue sharing setting to GetGlueSettings.
Merge branch 'better-settings-cats' into beta