Load Progress Bar 作成者: Luben Karavelov

This add-on adds a thin progress bar to each window while the page is still loading, like the inbuilt progress bar in Firefox for Android (code-named Fennec).

The color, size, opacity and position (top/bottom) are configurable from the add-on preferences.

The progress bar may return to official Firefox according to: https://bugzilla.mozilla.org/show_bug.cgi?id=1536932