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.

This can be used to combine e.g. the platform's SecureRandom
implementation with our own, so that a weakness in either source doesn't
harm security as long as the other source is strong.