Various fixes, changes and additions.

This is a large change, I've been testing as I go, and needs further testing.  Still making small changes here and there as I'm using it, but opened up a PR to get it tested, will comment again when I think I'm finished making tweaks.

Below is a list of most changes, there are probably some I've forgotten to document.

- Re-order extension points in addon.xml to fix RunAddon(script.trakt)
- Rename notification_service.py to service.py
- Rename NotificationService class to traktService
- Add new default.py as service entry point.
- Rename sync_exec.py to manual_sync.py for RunAddon entry point.
- Use a window property to cause service to trigger a manual sync.
- Add new class (syncThread) to handle synchronization (both manual and automatic).
- Alter scrobbler class to remove threading component, no long runs constantly along side main thread.
- Create a timer thread to send watched api calls, using an interval of 10 minutes.
- Fix some of my inconsistencies.
- Change Debug calls to use double quotes in all fiels.
- Change all dictionary key references to single quotes, and specific one word entries.
- Rename get_*_setting functions to getSettingAs, and utilize throughout.
- Add get/set/clear property functions.
- Add getString function to get language strings, and always return as .encode('utf-8', 'ignore')
- Scrobbler, fix multi-part scrobbling to send watched percent and duration of a single part, instead of the entire video.
- Scrobbler, move thread tasks to function that gets called from main service thread (update).
- Scrobbler, get episode/movie details at palyback start, instead of every watched() call.
- Scrobbler, move multi-part episode change checks to update() funciton and scrobble when needed.
- Scrobbler, use xbmc.PlayList to get palylist length instead of JSON-RPC call.
- Add startup delay setting, for those whose network isn't active right away, instead of increasing retry count.
- After a movie sync, output movie counts (from xbmc and trakt) to log, to help with incorrect movie counts.
- More small changes here and there, probably to many to document.