Merge pull request #28 from pyca/other-int-fixes

Add some missing test coverage for handling values of type `long` and make them pass by loosening the explicit type checks in various APIs.
Fill the send buffer with smaller strings in order to more completely fill it.

This makes the test pass on OS X.  Previously it failed with the
wrong exception type probably because there was enough room left
in the send buffer for the handshake to start.
Make sure we still write a lot of bytes, too.
Merge branch 'osx-wantwrite' into release-0.14

Fix the WantWriteError test on OS X (purely a test bug).