.buffer-newmessage => .buffer-newevent. newmessage is for plain/action

Rename the class that is added on a buffer event from `.buffer-newmessage` to `.buffer-newevent`.
If the buffer event is a Message.Type.Plain=1 or Action=4, the `.buffer-newmessage` class is also added.
Apply .on.off to .network when network.isConnected
Merge pull request #18 from Zren/networkoff

Apply .on.off to .network when network.isConnected
Merge pull request #15 from Zren/unread

.buffer-newmessage => .buffer-newevent. newmessage is for msg.type 1&4
Indicate which buffer is selected in the buffer list.

Does not indicate network status buffers as [data-buffer-id] is attached to the .network-name.
Renamed .active in the LESS (which was probably meant for this) to .channel.selected as .active is used in bootstrap.