Use finalizer() on SQLStmts again but us gc() before closing dbs.
Merge branch 'master' of git://github.com/quinnj/SQLite.jl into UDFs

More fixing of segfaulty stuff.
Neaten scalarfunc and improve error feedback.

Pull naming logic out of macro and add type annotations to the returned
function to prevent overwriting previously defined methods.

Let errors propagate, giving a more comprehensive traceback.
Add macro for preserving backslashes in strings.
Export and test sr_str.