Minor fixes

[xofe]

This PR contains a handful of minor/trivial fixes for some issues I've noticed. Most of these are patches I've been using in a personal build of uMatrix (and therefore have tested well!), and a few are small fixes/tweaks from uBO.

Each fix is contained in a single commit. Most are unrelated to each other, so if you'd prefer me to create an individual PR for each of them or remove any of them, just let me know.

Fixes:

• add a bottom border to the logger toolbar, so it doesn't blend in to the logger table entries
• fade-in tooltips when hovering buttons on the popup, like uBO
• add missing tooltip for the dashboard link on popup
• avoid CPU-costly Date.toLocale(Date|Time)String() in logger page (from uBO - gorhill/uBlock@02a79ea)
• add a favicon to the dashboard/logger pages + add i18n support for the logger title
• trashcan instead of X to remove an imported list (from uBO - gorhill/uBlock@efffa5e)
• minor fixes for the firefox and webext build scripts

[gorhill]

Looks all good to me, thanks!

[xofe]

Glad I could contribute!