add popup for server notice, warning and error

[alterratz]

Often when calling stored procedures in postgres you want do see warnings notices and errors from the db caused by "RAISE NOTICE, WARNING, EXCEPTION" statements. This change displays these servermesages in a popup box.

[lukemurray]

It would be great if this passed the error/information back to data-atom-controller or somewhere so each DB manager doesn't end up implementing this differently. Each should pass the information back and in one spot we can controll how it is displayed.