patch.js: Add url_engine... and key consistency

Together with min_build, this will be our way of checking for updates of the patch engine itself.
TPCState.php: Sensible return values for the file switch functions
Add basic spell card parsing

... which is enough for most of the games which don't have comments.
Move multi-line scraper to TPCUtil
Add spell card comment parsing
TPCUtil.php: Refactor wikitext sanitizing into its own function.

This way, it can also be used for single-line text. th07's "xx% Reflowering" spell requires this, for instance.