sqliteexecute() and sqlitecommit() commands

Code mostly taken from the ScraperWiki Classic [scraperwiki.php](https://bitbucket.org/ScraperWiki/scraperwiki-classic/src/6c23fb017064c956c5c565b267f34d4c96fc381a/scraperlibs/php/scraperwiki.php?at=default) module.

Not sure how to test it though!! I can't even get `scraperwiki::save()` to work in the *Code in your browser* tool.