Reconnect notification

Show an alert notification when the client is disconnected, and allow reconnecting immediately.
Fix a bug in StellarNetwork that caused 2 remotes to be created.

https://github.com/stellar/stellar-lib/pull/45 has to be merged and published before this is merged.
Fixes #918.
please avoid using global references where you can.  `module` is no longer available as of the last de-lint pass.

Instead, use `angular.module('stellarClient;)`