0.2.16 changes

[norrisjeremy]

• Add support for [email protected] KEX algorithm.
  -- This algorithm requires Bouncy Castle.
  --- sntrup761 prime sharedKeyBytes value not correct? bcgit/bc-java#1554 was opened for incompatibility in shared key size for SNTRUP761 with OpenSSH.
  --- bcgit/bc-java@db3ae60 was subsequently committed that should remedy this in next Bouncy Castle release.
  --- For now reflection is used to construct an SNTRUPrimeParameters instance that will output a compatible shared key size.
  -- The draft RFC specification for this algorithm is located at draft-josefsson-ntruprime-ssh.
• Clear intermediate copies of shared secret.
• Don't store unnecessary copy of shared secret.
• Clear copy of shared secret.
• Change normalize() method to a timing safe implementation.
• Add unit tests for normalize(), encodeAsMPInt() and encodeAsString() methods.
• Switch to bnd-maven-plugin in order to support Multi-Release OSGi bundle JAR's via supplemental manifest files.