cogl: avoid ‘_cogl_xyz_handle_new’ defined but not used warnings
cogl: avoid ‘_cogl_xyz_handle_new’ defined but not used warnings

This patch makes it so that only the backwards compatibility
COGL_HANDLE_DEFINE macro defines a _cogl_xyz_handle_new function. The
new COGL_OBJECT_DEFINE macro only defines a _cogl_xyz_object_new
function.

gcampax/cogl,Distrotech/cogl,Distrotech/cogl,gcampax/cogl,Distrotech/cogl,Distrotech/cogl,gcampax/cogl,djdeath/cogl,spatulasnout/cogl,spatulasnout/cogl,collects/cogl,collects/cogl,gcampax/cogl,djdeath/cogl-android,djdeath/cogl-android,djdeath/cogl-android,djdeath/cogl,djdeath/cogl