* plasma manager perf: speedup wait with a wait request object map
* removing duplicate == operator in plasma store
* fix serialization test
* code cleanup
* minor cleanup
* factoring out uniqueid hash and equality operators into common
* plasma manager: c++ify the WaitRequest struct
* plasma manager: get rid of the initial object request malloc
* cleanup
* linting
* cleanups and fix compiler warnings
* compiler warnings and linting