Automatically syncing after database error

[kevsmith]

We've been happy with epgsql but the need to manually sync after an error has caused us a few problems. These two commits enable pgsql_connection to automatically initiate a database sync in the event of a database error.

[wg]

Hi Kevin, thanks for the pull request!

I'm curious about what sort of errors you've encountered that could benefit from this, is it during binding parameters to a prepared statement or something else? I wonder if there are any cases where you wouldn't want to automatically issue a sync...

[devinus]

@kevsmith I'm curious as well.