gadget recalc - if you add a job...del and add again

if you add a job to do things like defer a calc till later in the loop
(or if later in size calc - it'd be the next loop run after rendering)
... then del the previous job and add a new one. why? order of
operation. if you add job a... because of event a, then add job b,
because of event b ... if for whatever reason, event a happens again
and you skip adding job a... job a will run before jbo b, even though
the LAST event is later and that 2nd event a may relay on event b
state/calculations. so always del then add to ensure then that job a
happens ater b if this scenario happens. it just leads to fewer
surprises and weird issues.

src/bin/e_gadget.c

@@ -140,7 +140,7 @@ _site_recalc_job_cb(E_Gadget_Site *zgs)
 static void
 _site_recalc_job(E_Gadget_Site *zgs)
 {
-   if (zgs->calc_job) return;
+   if (zgs->calc_job) ecore_job_del(zgs->calc_job);
    zgs->calc_job = ecore_job_add((Ecore_Cb)_site_recalc_job_cb, zgs);
 }