The ClutterCanvas content implementation should be used instead, to
avoid stringing along the ClutterTexture API and implementation.
This change requires some minor surgery, as the deprecated section
already contains an header for the previously deprecated methods; plus,
we don't want to deprecate clutter_cairo_set_source_color(). This means
creating a new header to be used for Cairo-related API.
GLib introduced macros that allows defining the lower and upper bounds
of the API to be used by application code.
The lower bound allows to define the minimum version that will trigger
deprecation warnings; the upper bound defines the maximum version that
will trigger compiler warnings for unavailable symbols.
This scheme allows gradually porting application code to a new version
of the API, especially in case of resynchronization after multiple
development cycles.
