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