Porting to latest Deferred and Swift2.1

[eryx67]

Major changes:

1. I didn't try to fix Results module. It was replaced with Either from Swiftz.
2. With latest Deferred socket object could be garbage collected when read/writes were still active. I made closing reader/writers on releasing socket less agressive by waiting queues to complete. To interrupt communication user has to call 'close' explicitly.

Tests were also fixed accordingly.