Fixed potential issues triggered by Diagnostics during browser startup.

This is a minor update, removing non-standard JavaScript syntax, which caused warnings in Firefox Aurora and Nightly builds.

* Updated to be compatible with Adblock Plus 2.7. Older Adblock Plus versions are not supported any more.
* The "ignore early returns" checkbox is gone — Diagnostics is no longer able to track low-level actions, so it generally cannot detect low-level calls that aren’t being forwarded to the upper level. However, there are relatively few such cases remaining in Adblock Plus now.
* The columns Context, Document and Additional have been removed as well — this kind of low-level context information is no longer available to Diagnostics (and neither to Adblock Plus when it is making decisions).
* The Request origin data has been extended. The tooltip will now show the entire frame hierarchy for a request, not only the location of the frame immediately responsible.
* The new Private column will indicate whether a request is associated with a private browsing window.
* The Type column will no longer attempt to localize the type, instead the internal type identifier will be displayed (corresponds with filter options).