Added a few features from Vimperator

[wgreenberg]

Added three new commands:

• Vomnibar.activateWithCurrentUrl: opens the vomnibar, but pre-populates it with the current URL. Especially useful if you want to navigate to a slightly different URL path. I tend to map O to this, and o to Vomnibar.activate
• Vomnibar.activateWithCurrentUrlInNewTab: the same as above, but opens the resulting URL in a new tab. I usually map t to Vomnibar.activateInNewTab, and T to this
• removeTabAndGoLeft: the current removeTab command closes the current tab, and leaves the user on the tab to the right of where they were. This just does the opposite. As an example, I map d to removeTab and D to removeTabAndGoLeft

[smblott-github]

I'm not sure the case is strong enough for any of these to warrant adding more new commands. Chrome itself has pretty good shortcuts in its omnibar.

As for removeTabAndGoLeft, this is indeed a common case; but does it warrant a whole command to itself? With my own mappings, I get this effect with x<, which isn't exactly burdensome.

Also, although it's been around for a while, the proposal doesn't seem to have generated a lot of support. So closing, for now. But thanks for the contribution!

[smblott-github]

Actually, I see now we got the first two of your commands in #1004.