Refactor of Connections
Constants for address types
Make constructors public instead of package private since connections are not in same package anymore
Replace println() with logger calls
Simple key agreement for CREATE_FAST
Changes to support new connection cache, CREATE_FAST, and directory streams
Directory stream changes
Remove debug output
New DirectoryDownloader replaces old NetworkStatusManager
Use new refactored ConnectionCache and DirectoryDownloader components
Merge remote-tracking branch 'origin/master'