Add vim's 'ctrl+d','ctrl+u','g g', and 'G' actions

* 'd' - scroll down half page
* 'u' - scroll up half page
* 'g g' - scroll to top of page
* 'G' - scroll to bottom of page
Open up link hint characters for user modification
Upgrade mousetrap

Mousetrap now supports overriding stop behavior instead of us having to
hack it (via Mousetrap.stopCallback).

Also, it fixes a shift-F issue in inputs since newer mousetrap has
better input detection.
Make escape blur inputs

This effectively makes a 'normal mode' feeling by allowing you to
always get out of the other modes.

Especially effective if you don't use a modifier key to prefix commands.
Fake an 'insert mode' by pressing 'i'

Really, it is just a user-requested way to stop actions from happening.
Restore previous input behavior w/ modifiers

Previous to the last mousetrap upgrade, when using a modifier key to
prefix commands, these commands were available even inside inputs. This
behavior was lost when mousetrap was upgraded to 1.3.

This commit restores that behavior.
Merge pull request #13 from woahdae/modes

Add 'normal mode' and 'insert mode' behavior
Merge pull request #15 from woahdae/user_mod_link_hints

Open up link hint characters for user modification
Merge pull request #12 from woahdae/more_actions

Add vim's 'ctrl+d','ctrl+u','g g', and 'G' actions
Updated to v 1.7
Remove console.log calls
Pressing 'x' now closes the current tab
Added 'ctrl+[' combo as escape sequence.
Merge pull request #18 from connor/x_close_tab

Pressing 'x' now closes the current tab
Merge pull request #17 from marcosdsanchez/patch-1

Remove console.log calls
Version 1.8

Log lines have been removed
Ctr-X now closes the tab
Added h, l, H, L, X

Added:
h (scroll left 60px)
l (scroll right 60px)
H (back)
L (forward)
X (close tab and select tab to the right)
Merge pull request #23 from brandonhorst/bh_dev

Added h, l, H, L, X
Added step size slider to Settings panel
Added ability for users to blacklist URLs via the extension settings screen