DuplexOutgoingSession flushes its output stream if it's idle for a
transport-defined interval, causing an empty frame to be sent. The TCP
and Tor plugins use a socket timeout equal to twice the idle interval to
detect dead connections.

See bugs #27, #46 and #60.

It's in the git history if we ever decide to use it.

This fixes some lint warnings and may also fix dev task #102.

Android L requires executables to be compiled with PIE support, so we'll
have to ship two Tor binaries.

See bug #27.

The TransportReader/Writer's dispose() method should handle that, and
ConnectionManager is responsible for calling it.

This makes it more likely that connections will be closed cleanly.
However, the interrupt() method is currently ineffective for incoming
sessions as it won't interrupt a blocking read, e.g. when the packet
reader is waiting for a packet.

Because that's what it does.