Redis connection lost not detected

[jgm1986]

The method isConnected inside DataBase class doesn't works as expected. If the KeyServer lost the connection to the Redis database, nothing happens. Fix this problem with these actions:

1. Shows an alert when the the connection was lost with the database.
2. Try to reconnect automatically.

During the step number 2, the KeyServer administrator shoud be able to:

• Show help menu options (H).
• Show KeyServer status and details (I).
• Close KeyServer tool (Q).

[jgm1986]

Now the KeyServer can alert and reconnect automatically during a problem with the database connection.