Initial stub
Add the message count label (static for now)
Hook into the shell to get notified when the message count changes
Keep the label with the number of message updated
Remove the actor (and not a random object) when disabling
Add a nice red background to the counter
Show the count only if there are unread messages
Add an empty (for now) README file
Add a simple Makefile
Space the counter like the other elements
Add make targets to enable/disable the extension
Give more explanations on how to use the Makefile
Update the README file
Add an AUTHORS file
Set the git repo as URL for the extension
Implement a graphical notification.

Hat tip to 'a09alehu' on
<https://bugzilla.gnome.org/show_bug.cgi?id=641723#c81> for the
suggestion.
Makefile: improve UUID-grabbing rule

Previously this failed if the JSON block was all on one line, as the one
generated by gnome-shell-extension-tool is.
It's not Christmas any more
Move all the code out of init()
Add a Makefile target to generate a .zip for extensions.gnome.org