ISPN-3315 Retry remote get after topology change if all the targets are no longer owners

* Added test case to cover all possible inter-leaving scenarios between a
remote get and state transfer

* changed the remote get algorithm to retry when the topology id changes
ISPN-2999 Fixed in ISPN-2281 but added tests for getCacheEntry + DIST
describe how one can preview the generated documentation
ISPN-3681 enhance the documentation of the new persistence API

* updated the SPI documentation
* updated the jdbc and file store to relfect the new names
* updated the javadoc links to point to 6.0
ISPN-3712 Add ByteArrayKey to the 5.2.x compatibility layer so that the HotRod target migrator can read keysets
          from 5.2.x servers
ISPN-3714 No need to wrap ClassLoaders in WeakReference in invocationContext implementations
ISPN-3715 SingleKeyNonTxInvocationContext is not using the provided KeyEquivalence