bitcore-lib gets confused when more than one network uses the same xpriv bytes

[gpip]

Hello,

When adding a network that shares the same xpriv bytes as another, HDPrivateKey will return the incorrect network because it bases its decision only on those bytes. Should it store the actual network used instead? Maybe the network name?

> var b = require('bitcore-lib');
> var c = require('coininfo');
> var dashmain = c.dash.main.toBitcore();
> dashmain.name = 'dash';
> dashmain.alias = 'dashmainnet';
> b.Networks.add(dashmain);
> b.HDPrivateKey('dash').network
'dash'  # OK
> b.HDPrivateKey(b.Networks.mainnet).network
'dash'  # FAIL

Without modifying:

> var b = require('bitcore-lib');
> b.HDPrivateKey(b.Networks.mainnet).network.name
'livenet'  # OK

[priestc]

#145 may fix this issue