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.
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
Structured passkeys, internally and on the options and popup pages.
Fix regression: reinstate confirmation dialog for restoreToDefaults
Retain excludedUrls setting, so testers can revert to previous versions.
Structured exclusion rules: Fix typos and minor issues.
Structured exclusion rules: Simplify isEnabledForUrl.
Changed to show url when item selected
Merge pull request #1142 from luanpotter/master

Suggestion for impl of #1141
Structured passkeys; changes following code review; major rewrite of options.
Add some style advice

These represent common feedback given on PRs
Add some guidelines for PRs
Clearer reset-to-defaults confirmation message.
Merge pull request #1154 from smblott-github/passkeys-structured

Structured exclusion rules internally, and on the popup and options pages.
Merge pull request #784 from deiga/patch-3

Add links-hint mode to download links
Merge branch 'feature/edit-url-in-vomnibar' of github.com:sukima/vimium into sukima-feature/edit-url-in-vomnibar

Conflicts:
	background_scripts/commands.coffee