update proposal op

solves

#45 (closed) #44 (closed) #39 (closed)

Waiting on the first review before making the unit tests

manual tests:

create_account "initminer" "howo" "" true
transfer_to_vesting "initminer" "howo" "10000.000 TESTS" true
post_comment howo "test" "" "tag" "title" "body" "" true
transfer  initminer howo "2500.000 TBD" "" true

create_proposal howo howo "2020-05-22T03:00:00" "2020-05-28T04:00:00" "200.000 TBD" "cool proposal vote me" "test" true

find_proposals [0]

the above should output: 

[{
    "id": 0,
    "proposal_id": 0,
    "creator": "howo",
    "receiver": "howo",
    "start_date": "2020-05-21T03:00:00",
    "end_date": "2021-05-21T03:00:00",
    "daily_pay": "200.000 TBD",
    "subject": "cool proposal vote me",
    "permlink": "test",
    "total_votes": 0
  }
]

update_proposal 0 "howo" "100.000 TBD" "cool proposal" "test" true
find_proposals [0]

[{
    "id": 0,
    "proposal_id": 0,
    "creator": "howo",
    "receiver": "howo",
    "start_date": "2020-05-21T03:00:00",
    "end_date": "2021-05-21T03:00:00",
    "daily_pay": "100.000 TBD",
    "subject": "cool proposal",
    "permlink": "test",
    "total_votes": 0
  }
]

get_account_history howo 0 1000