feat: expose settings via node api (#254)

* Added "Get settings" node endpoint for route: /settings

* Change settings "genesisAmount" from 10000000000000 to 5000000000000
* Change settings "incomeBase" from 50000000000 to 100000000000
* Change settings "incomeLimit" from 10000000000000 to 5000000000000

feat: rename is registered output field (#253)

BREAKING CHANGE: Node and UI server APIs have changed.
1. Node
* Modified:
  - UTXO and Output data structures "has_income" field have been renamed to "is_yielding"
  - Block data structure fields have been reordered:
    - Block data structure was:
    {
      "timestamp":                    int64
      "previous_hash":                [32]byte
      "transactions":                 []Transaction
      "added_registered_addresses":   []string
      "removed_registered_addresses": []string
    }
    - Block data structure is now:
    {
      "previous_hash":                [32]byte
      "added_registered_addresses":   []string
      "removed_registered_addresses": []string
      "timestamp":                    int64
      "transactions":                 []Transaction
    }
2. Node and UI server
* Modified:
  - Output data structure "has_income" field has been renamed to "is_yielding"

fix(p2p): the main network is not single port scoped (#210)

feat(node): rename last blocks request field (#207)

BREAKING CHANGE: The endpoint for getting the last blocks has changed.
* the request value to get last blocks was:
LastBlocksRequest {
  StartingBlockNonce int
}
* the request value to get last blocks is now:
LastBlocksRequest {
  StartingBlockHeight uint64
}

fix(node): registered addresses might become too big (#195)

fix(node): total amount verification is wrong (#194)

fix(node): requesting last blocks corrupts the blockchain (#192)

fix(node): there is no minimal transaction fee (#190)

fix(node): transactions can be older than 1 block (#189)

feat(node): reduce blocks request time (#185)