Set iota node in settings

[DanielPollithy]

Choose from http://iota.dance/nodes

[tobywoerthle]

http://iotasupport.com/lightwallet.shtml

Might try this one as default:

http://iota.bitfinex.com:80
Connect your GUI wallet to this distributed, geo-balanced service via this DNS link

Will add setting to configure, but not priority right now as we'll be using the private testnet.