enhancement/bug: compare to db connection details lost when user attempts to cancel compare

[githubmarker]

1. use "compare to db" and fill in details
2. select another record, or open another dat file
3. click compare to db
4. prompt appears asking user whether to reuse the same connection details

expected behavior:

• a way to cancel the compare without losing connection details and needing to re-enter them

actual behavior:

• the only way to stop the compare is to click no, but this also forgets previously entered database connection details, even if no replacement details are supplied

possible solutions:

• add a cancel button
• if not replacement connection details are supplied, remember previous details the next time the compare to db button is clicked.

suggested labels: enhancement or possibly bug

[tslater2006]

I'm pretty sure this is fixed by my fixes for #9. Specifically the DB connection management is no longer tied to the compare button but managed separately by the Database toolbar option.