Errors are properly handled and reported on non-generated statements
as well now.  Also gets rid of connection handle leak.

This gets rid of the regexp-matview-optimization.

Some instances died with "basic_string::_M_construct null not valid".
Maybe it happened here.

This allows access to the sqlstate and ought to get rid of the
confused transaction state bug.

Closes #12, closes #13.

By materializing a single regexp from all lines in known_re, the CPU
load by filtering goes down by 90%.

Closes #12.

This can be sorted, making updating them more lightweight because
diffs are smaller and probably also GIT's delta compression works
better.

Suggested by @zesoup.