configure.ac: Add --enable-uoa option.
configure.ac: Add --enable-uoa option.

Enables support for Ubuntu's own "Online Accounts" framework.

Adds the following library dependencies:

    libaccounts-glib
    libsignon-glib
    json-glib
    rest-0.7

And defines a HAVE_UOA conditional.

tintou/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,Distrotech/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,Distrotech/evolution-data-server,matzipan/evolution-data-server,Distrotech/evolution-data-server,Distrotech/evolution-data-server,tintou/evolution-data-server,Distrotech/evolution-data-server,matzipan/evolution-data-server