Enhancement: support for disabling site-specific access keys

[dumblob]

First, thanks for this great extension - I'm using pentadactyl, but at work I have to use Chrome on Windows and because other vim-inspired extensions for Chrome don't work very well, this one saved my life.

Anyway, I'm stuck with few bugs (features?) and the biggest one is the lack of possibility to completely disable all site-specific access keys (usually in DOM as accesskey attribute of different tags).

Do you think it would be possible to add some directive which would disable them? In pentadactyl, the keys which collide with pentadactyl key bindings (including user-specified key bindings) are not pass through and thus collisions never happen contrary to Vrome.

These access keys can be found e.g. in many web-based email clients (e.g. the one used by volny.cz and centrum.cz) or similar desktop-app-mimicking web pages.