Fix unit test formatting

Replaced mixed use of tabs and spaces with just spaces. This makes the
unit test code formatting consistent with the SQLitePlugin.js code
formatting.

Also includes some other misc formatting inconsistencies.
Invoke transaction error callback with the error that caused the failure

This fix updates the plugin so that the transaction error callback is
invoked with the error from the statement that caused the transaction
to fail and rollback.

Previously only the executeSql error callback would be invoked with the
error.

This mirrors the behavior of the HTML5 Web SQL
API.

Includes unit tests.