Fix make package script
Actually make the Managers singletons so they can be called from elsewhere
Add {set,get}_max_{upload,download} functions in the SettingsManager
Add first parts of the RateLimiter to the DownloadManager
Enable ratelimiter with 15s intervals
Misc small fixes
Merge pull request #144 from wtud/tribler-maxdlup

Add RateLimiter to DownloadManager