evas render: fix updates sometimes are list of rects sometimes updates

evas render: fix updates sometimes are list of rects sometimes updates

ssometimes the evas render updates are a list of Render_Updates
structs ... sometimes Eina_Rectangles. this is horrible and i think a
bug turns up (but its not reproducable on linux - just bsd) with an
invalid free ... likely because we free() a ptr from the mem pool
eina_rectangle gets rects from. thats most likely the cause of
https://phab.enlightenment.org/T3226 - but as i can't know for sure,
this is a guess, but readiong the code i see posible vectors of
problemss here ... maybe.

so this redoes the update rects to ALWAYS be Render_Updates struct
and appropriately returns correct structures etc. etc. in api which
demand a list of Eina_Rectangles there.

pending testing on foreign sysstems to confirm this by @netstar

@fix