many bugfixes, option to turn on/off logging
+ added option to turn on/off logging for clients and trackers
* clients and trackers dont load previous state by default - one must do
it manually if desired. File Transfers load their state upon being
loaded into a client.
* when resuming seeding, exception was being thrown as having no
metadata
* stops all downloading threads/tasks when download is complete
* minor code refactorization