* Reimplement tools, starting with a spiffy AJAX expression tester. Didn't bother implementing as non-AJAX, as it's just an extra.
* Change exchange protocol between native parser and PHP app. Resulted in 2-3-fold performance boost.
* Fix minor bug from last night.
* Introduce a syntax check on-save.
* Introduce filter history (requires DB schema change).
* Deprecate now non-working /tools interface (will come back).
* Allow matching on the changes made in an edit (added/removed lines, etc)
* Improve display of variables in details view - standardise the table size, add white-space: pre, font-family: monospace.
* Improve modifiers: add htmlencode/htmldecode/urlencode/urldecode.
* Add 'abuse filter tools', currently consisting of a testing ground for the modifiers. In future, may include facilities for testing filters against user contributions, recent changes, or other sources.
* Disallow more than 100 condition-checks per action.
* Disallow filters which are misbehaving (more than 5 matches, constituting more than 5% of recent actions)
* Display statistics for all filters (percentage of times the condition limit is reached, and percentage of times some filter is matched), and individual filters (percentage of times it's matched).
