Frame reordering window.

api/net/sf/briar/api/transport/TransportConstants.java

components/net/sf/briar/transport/ConnectionWindowImpl.java

components/net/sf/briar/transport/FrameWindow.java

components/net/sf/briar/transport/FrameWindowImpl.java

components/net/sf/briar/transport/HeaderEncoder.java

...s/net/sf/briar/transport/IncomingAuthenticationLayer.java

...t/sf/briar/transport/IncomingAuthenticationLayerImpl.java

.../net/sf/briar/transport/IncomingErrorCorrectionLayer.java

components/net/sf/briar/transport/NullFrameWindow.java

.../sf/briar/transport/NullIncomingErrorCorrectionLayer.java

.../net/sf/briar/transport/NullIncomingReliabilityLayer.java

test/build.xml

test/net/sf/briar/transport/FrameWindowImplTest.java