This adds advanced options for toggleMuteTab.

Examples:

   map X toggleMuteTab all
   map Y toggleMuteTab other

In the first case, all audible, unmuted tabs are muted; otherwise all
muted tabs are unmuted.

The second case is the same, except that the current tab is excluded
from consideration.

Follow on from #2269.

Use prefix matching for global marks.

If the user is jumping to a scroll position within a tab, then we need
an exact match on the URL (because otherwise the scroll position doesn't
really have a meaning).  Otherwise we only require a prefix match, a la #2250.

This changes the logic for selecting an existing tab when using global marks.

Previously, an exact RUL match was required.  Here, we only require a prefix match.

For example, if the global-mark URL is:

    https://inbox.google.com/u/0/

Then a tab with the URL

    https://inbox.google.com/u/0/sent

will be selected.

This is a more usable approach when the user uses global marks to visit
important sites like gmail, Facebook or Twitter.  On these sites, the
URL changes, but the user still thinks of the tab as their "gmail tab",
for example.

Also, when choosing between multiple candidate tabs:

- If there is at least one candidate in the current window, then only consider candidates in the current window.
- If there are more than one candidates, then don't select the current tab.
- Finally, select the remaining candidate with the shortest URL.

Closes #2248.