Add SuppressFinalize calls to Dispose()

Best practices suggest to add a SuppressFinalize call to the Dispose()
method. This tells the garbage collector that it doesn't have to call
the expensive finalizer on this object.
Merge pull request #67 from ermshiperete/SuppressFinalize

Add SuppressFinalize calls to Dispose()
Merge pull request #68 from JohnThomson/styleControl

Tabbed format dialog allowing style name choice