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.
`force_reconnect` needs to be exposed on the StellarNetwork itself.  You should not be reaching into StellarNetwork to get the raw remote object.  It's not guaranteed to be present.

While not to be considered dogma, the ideas here: http://en.wikipedia.org/wiki/Law_of_Demeter  are very useful to improving your software.