Rename crypto methods and constants for Bluetooth key agreement

...g/briarproject/android/invitation/AddContactActivity.java

...-api/src/org/briarproject/api/crypto/CryptoComponent.java

...core/src/org/briarproject/crypto/CryptoComponentImpl.java

...-core/src/org/briarproject/invitation/AliceConnector.java

briar-core/src/org/briarproject/invitation/BobConnector.java

briar-core/src/org/briarproject/invitation/Connector.java

...r-tests/src/org/briarproject/crypto/KeyAgreementTest.java

...rc/org/briarproject/crypto/KeyEncodingAndParsingTest.java