Add favicons to vomnibar completions

Favicons are displayed as a background-image style next to urls in
similar style to chrome's history page.
For tabs the icon is fetched from the url specified by chrome tab's
favIconUrl property. Unfortunately extensions to not have access to
chrome://favicons/ to get bookmark favicons but fortunately most sites
serve a favicon from protocol://hostname/favicon.ico
(e.g. http://example.com/favicon.ico) so this url is tried for non-tab
types.
Add Vomnibar.activateEditUrl commands

Often times when I'm working on sites I want to add a query string or
modify the port number. The go up one level or root of the URL commands
are nice but they don't alow you to add or remove specifics on the
current URL.

This adds two commands that act exactly like the normal onmibar open but
populates the bar with the current URL.

I picked `ge` as the default and `gE` as the default for the same in a
new tab.
Only block keyup for keys where we have handled a keyup/press event

Fixes the issue of Vimium indiscriminately capturing keyup events,
introduced in PR #978.
Merge pull request #1130 from mrmr1993/fixKeyupCapture

Only block keyup for keys where we have handled a keyup/press event
Added feature to download links
Update link_hints.coffee
Suggestion for impl of #1141
Changed key biding to use right arrow instead of tab, returning previous tab functionalities
Switching again to Ctrl+Enter
Allow passing of keys to the underlying page.
Allow passing of keys to the underlying page (minor code review).
Allow passing of keys to the underlying page (more minor code review).
Allow passing of keys to the underlying page (populate page popup with existing rule).
Allow passing of keys to the underlying page (fix/maintain order of exclusion list).
Allow passing of keys to the underlying page (slight reformatting of page popup).
Allow passing of keys to the underlying page (comments can start with " too).
New icons for partially enabled, for passkeys.
Better state management for passkeys.
Better icon for passkeys.
Do not call handlers which do not exist.