BigChainDB Java Driver Changes - Loggers, Websocket Session Manager, JDK 1.8

[alvin-reyes]

• Introduce Loggers on each API classes
• Introduce Websocket Session Handler
• Force build using JDK 1.8
• Parameterized Output, Inputs and Operations
• Renamed Globals to BigChainDbGlobals
• Merged new changes from main branch

[alvin-reyes]

@bodia , @tzclucian - My next one is to remove the JSON library. After that, we can discuss streamlining the release process.

[bohdanbezp]

Sorry for such a long delay reviewing this. Looks very good.