dictextension dict

Call onError when onHaveDictionaries throws an exception.
This makes it easier to track down bugs.

Fix whitespace.

Remove some extraneous logging of error codes that was accidently committed.

Use a data-driven approach for populating the strategy droplist
with a set of default choices, instead of hard-coding it into
multiple places in the logic.

Use a data-driven approach for populating the database droplist
with a set of default choices, instead of hard-coding it into
multiple places in the logic.

Use a grid element so that the labels for the "databases" and "strategies"
drop-lists are inline with the droplists. This saves vertical space.

Add support for choosing the strategy for the default server.
The support is functional, but the implementation is somewhat
rough and will require some further tweaks and refactoring.

Fix a bug where selecting a server that never responds
to the DICT commands put the preferences into a bad state.

Compute nsIPrefBranch once and save it in DictExtension

Use the new name of DictExtension.getDefaultServerDatabaseName()