Poseidon Hash/RAMT/SMT

[albertog78]

To be able to not have to collect first all the inputs together and then passing them to poseidon, expose via JNI the new implementation coming from ginger lib (HorizenOfficial/ginger-lib#56)

[DanieleDiBenedetto]

It's needed to expose also the new MerkleTrees in branch https://github.com/HorizenOfficial/ginger-lib/tree/smt

[DanieleDiBenedetto]

Done and merged for UpdatablePoseidonHash and InMemoryOptimizedMHT. SMT needs some rework and was not merged for the moment. SMT will be introduced in the future as part of #43, but SMT itself still needs some work (see HorizenOfficial/ginger-lib#75 )