Added new classes to support saving data.

The ConversionConfiguration class is intended to be the class that
contains all the settings for executing the application's conversion
functionality.  In the future, this class will be serialized to an XML
file, which can be loaded back into the application to invoke the
conversion process unattended.
Implemented saving and loading configurations.

It currently does not work for the list of tables, but it does a great
job of populating the fields on the main screen.  This will save us some
time in the future.
Implemented support for saving selected tables.

Once tables are selected, the dialog to choose them no longer appears.
This isn't ideal, but it does provide a bit of automation that didn't
exist prior.