Change `new Address` to `Address.new`

Documentation says `new Address(...)` but following the examples produces

      return new Address(addr);
             ^
    TypeError: object is not a function
        at /Users/johnbackus/bitcore-testing/validate-example-broken.js:9:10
        at Array.map (native)
        at Object.<anonymous> (/Users/johnbackus/bitcore-testing/validate-example-broken.js:8:3)
        at Module._compile (module.js:456:26)
        at Object.Module._extensions..js (module.js:474:10)
        at Module.load (module.js:356:32)
        at Function.Module._load (module.js:312:12)
        at Function.Module.runMain (module.js:497:10)
        at startup (node.js:119:16)
        at node.js:901:3

Changing `new Address` to `Address.new` fixes this.  From the "Validating an address" example:
```shell
    $ node validate-example-broken.js

    /Users/johnbackus/bitcore-testing/validate-example-broken.js:9
      return new Address(addr);
             ^
    TypeError: object is not a function
        at /Users/johnbackus/bitcore-testing/validate-example-broken.js:9:10
        at Array.map (native)
        at Object.<anonymous> (/Users/johnbackus/bitcore-testing/validate-example-broken.js:8:3)
        at Module._compile (module.js:456:26)
        at Object.Module._extensions..js (module.js:474:10)
        at Module.load (module.js:356:32)
        at Function.Module._load (module.js:312:12)
        at Function.Module.runMain (module.js:497:10)
        at startup (node.js:119:16)
        at node.js:901:3

    $ node validate-example-fix.js
    1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa: is valid
    1A1zP1eP5QGefi2DMPTfTL5SLmv7Dixxxx: is not a valid address. Error: checksum mismatch
    A1zP1eP5QGefi2DMPTfTL5SLmv7Dixxxx: is not a valid address. Error: checksum mismatch
    1600 Pennsylvania Ave NW: is not a valid address. TypeError: Unspecified operation for type undefined for add

    $ diff validate-example-broken.js validate-example-fix.js
    9c9
    <   return new Address(addr);
    ---
    >   return Address.new(addr);
```