Fix an issue with notifications being shown when fetching old lines

@xt, does this fix the issue for you?

While we're at it, fix the annoying jump-to-bottom when loading more lines.
Add method to retrieve inputNode element from directive
Work with inputNode element directly

Instead of using $scope.command, we work with the inputNode element
directly to have control over the caret position. This let us have
nick completition in the same way as WeeChat.

Fix #74
Remove unnecessary id

Encapsulating the feature in a angular directive let us avoid
setting global ids for elements.
Merge pull request #171 from lorenzhs/fixduplicatenotifications

[WIP?] Fix an issue with notifications being shown when fetching old lines
Merge pull request #178 from cormier/fix-74

Fix nick completion issues
Let user specify the id of the input bar

Input bar id is not globally set, but passed to the directive
through the input-id attribute.
Move activeBufferChanged listener to WeechatCtrl

I don't believe that the inputBar directive should know about the
mobile cutoff we have set for GB. We should aim to make it as
reusable as possible
Set container to panel
Merge pull request #186 from torhve/container-panel

Set container to panel
Merge pull request #185 from cormier/fix-input-bar

Fix input bar