Merge branch 'static-transport-keys' into 'master'

...briarproject/bramble/api/contact/ContactExchangeTask.java

.../org/briarproject/bramble/api/contact/ContactManager.java

.../org/briarproject/bramble/api/contact/PendingContact.java

...briarproject/bramble/api/contact/PendingContactState.java

...le/api/contact/event/PendingContactStateChangedEvent.java

.../org/briarproject/bramble/api/crypto/TransportCrypto.java

...va/org/briarproject/bramble/api/db/DatabaseComponent.java

...project/bramble/api/db/NoSuchPendingContactException.java

...project/bramble/api/db/PendingContactExistsException.java

...oject/bramble/api/keyagreement/KeyAgreementConstants.java

...rproject/bramble/api/transport/AbstractTransportKeys.java

...g/briarproject/bramble/api/transport/HandshakeKeySet.java

...briarproject/bramble/api/transport/HandshakeKeySetId.java

...org/briarproject/bramble/api/transport/HandshakeKeys.java

.../org/briarproject/bramble/api/transport/IncomingKeys.java

...va/org/briarproject/bramble/api/transport/KeyManager.java

.../org/briarproject/bramble/api/transport/OutgoingKeys.java

...riarproject/bramble/api/transport/TransportConstants.java

...g/briarproject/bramble/api/transport/TransportKeySet.java

...briarproject/bramble/api/transport/TransportKeySetId.java