Two problems:
(a) Vala 0.22.1 fixes a binding change in libnotify
that has to be fixed but causes Geary to be unable to build on prior
versions of Vala. libnotify.vapi added to solve this problem.
(b) New version of Vala appears to be more sensitive to detecting
problems in .gir files. Using our .metadata file to paper over these
issues in WebKit-3.0.gir.
