H2 was failing to load its driver class on OpenJDK 6 because the code was compiled for Java 7.

Show setup page error messages by the relevant text box

Closes #159 

See merge request !3

Hide password strength meter when confirming password

Closes #100

I opted to hide the strength meter because:

* more extensive changes would have been required to set the strength meter to 100% red.
* IMHO it would lead to confusion as to the meaning of the strength meter.
* the "passwords do not match" error should eventually become a proper error of the confirm EditText, not a separate label.

See merge request !2

Clear the password field if wrong password is entered

Closes #150

See merge request !1

"synchLock" will become confusing when we have lots of objects with "sync" in the name.

This breaks backward compatibility for the wire protocol and messages
stored in the database. The database schema version has been
incremented.