Sync on a per subreddit basis

Emote list is now saved per subreddit, this allows the app to
only download and load emote lists that are set to sync. It also
allows us to process the emote list in smaller batches, improving
memory usage.

Subreddit sync now run concurrently in up to 4 thread to improve
sync performance.

Subreddit information is now also saved, allowing consumers to
filter based on subreddit
Removed executable attrib
Updated logback to version 1.1.1-3
Bump version to 1.3.0
Updated subreddit list