Fixes on swipeWallet and unspent

This was created to help user bitssaphire are reported on
    https://github.com/bitpay/copay/issues/1585
  and later gitter conversation.

1. It seems that sometime Insight report UTXO without scriptPubKey (must be a broken cache) and that broke the TransactionBuilder and therefore no TX could be generated. This PR only add a filter to Insight.js to workaround that problem. 
2. When a TX had to many inputs the UX crashed and the generated TX was impossible to broadcast.

Fixes:  https://github.com/bitpay/copay/issues/1701
Fixes:    https://github.com/bitpay/copay/issues/1585