Request reader and unit test.

api/net/sf/briar/api/protocol/Ack.java

api/net/sf/briar/api/protocol/Offer.java

api/net/sf/briar/api/protocol/Request.java

...nents/net/sf/briar/db/ReadWriteLockDatabaseComponent.java

...onents/net/sf/briar/db/SynchronizedDatabaseComponent.java

components/net/sf/briar/protocol/AckFactory.java

components/net/sf/briar/protocol/AckFactoryImpl.java

components/net/sf/briar/protocol/AckImpl.java

components/net/sf/briar/protocol/OfferFactory.java

components/net/sf/briar/protocol/OfferFactoryImpl.java

components/net/sf/briar/protocol/OfferImpl.java

components/net/sf/briar/protocol/ProtocolModule.java

components/net/sf/briar/protocol/RequestFactory.java

components/net/sf/briar/protocol/RequestFactoryImpl.java

components/net/sf/briar/protocol/RequestImpl.java

components/net/sf/briar/protocol/RequestReader.java

test/net/sf/briar/db/DatabaseComponentTest.java

test/net/sf/briar/protocol/AckReaderTest.java

test/net/sf/briar/protocol/FileReadWriteTest.java

test/net/sf/briar/protocol/RequestReaderTest.java