Update dependencies

[framillien]

Update jsch to last version (security fix & new algos)

Remove additionnal SSH lib

JCraft Jsch lib is the main SSH lib used. J2SSH is only used for a passphrase validity check. Replace J2SSH by Jsch calls to implement validity check.

Allow packaging with JDK 9, updating tests lib

Previous PowerMock implementation is not compatible with Java9, upgrade PowerMock, Mockito & co to gain this compatibility.

Do needed changes (null parameter is no more matched by any() matchers) and try to use same patterns for static Mock imports:

• By default import static methods of Mockito
• Import harmcrest static matchers when necessary
• Never import static method of PowerMock: We need to know when we use PowerMock to limit his usage