Hello,

Thanks for maintaining this library package, I've used it to make things
easier for reaching services that are reachable only on localhost on
certain machines.

I've just encountered a bug with the currently available version where
using the default parameter value of host_pkey_directories=None when
creating a class of type SSHTunnelForwarder does not search for keys
inside the default ~/.ssh directory, contrary to what is documented in
the code.

I've looked upstream and this problem was solved in newer releases.

Whenever it is convenient for you, could you please bump the library's
version? Currently there is 0.4.0 available on github.

Cheers!