[RPC] Add listaddresses

[CaveSpectre11]

Problem

There is no real handy way to see your stealth addresses

Solution

Add listaddresses, which will return your basecoin and stealth addresses, and your stealth change address if it has a balance.

Testing

$ veil-cli help listaddresses
listaddresses (type)

Lists addresses in the wallet Address Book.

Arguments:
1. "type"       (string, optional) receive - all receive addresses (default).
                                   balances - all receive addresses with balances.

Result:
[
  {
    "address",  (string)  The veil address
    amount,     (numeric) The amount in VEIL
    "label"     (string)  The label
  }
  ,...
]

Examples:
> veil-cli listaddresses
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "listaddresses", "params": [] }' -H 'content-type: text/plain;' http://127.0.0.1:58812/

.$ veil-cli listaddresses
[
  {
    "address": "bv...",
    "amount": 0.00000000,
    "label": "Label 1"
  },
  {
    "address": "bv...",
    "amount": 1.00000000,
    "label": "Label 2"
  },
  {
    "address": "bv...",
    "amount": 0.00000000,
    "label": "Label 3"
  },
  {
    "address": "sv1qqpxazw8vnxv5wrswqs0g0xntwcaezqutse8gsy8ycuwykpw9pjhkdspq29jt3megknpu38zl5r58pfl96vr56596es3gpx4ey4xaad2shjpcqqqgh8ut0",
    "amount": 0.00000000,
    "label": "Donations"
  },
  {
    "address": "sv1...",
    "amount": 0.00000000,
    "label": "stealth"
  },
  {
    "address": "sv1qqpj9l2f883k7ucs88xdzrcuus8wr6jzrnk85quv3p2u90zwyy6d5tqpq0fl2ksmvlsf5hfddf8ezqnph5q6zf05cmac28g6ytafdzp8aufsuqqqwk9ep3",
    "amount": 0.00000000,
    "label": "Dev Bounty"
  },
  {
    "address": "sv...",
    "amount": 0.00000000,
    "label": "Stealth 2"
  },
  {
    "address": "sv...",
    "amount": 2.00513045,
    "label": "<stealth change address>"
  }
]

$ veil-cli listaddresses balances
[
  {
    "address": "bv...",
    "amount": 1.00000000,
    "label": "Label 2"
  },
  {
    "address": "sv...",
    "amount": 2.00513045,
    "label": "<stealth change address>"
  }
]

[CaveSpectre11]

This partially addresses #772

[codeofalltrades]

ACK 91e5bdc