made collection view more extensible
made collection view more extensible

can now control how item view instances are
created, mostly useful for child views in your
item views

Change-Id: Ic09e39556f371851744a48f3724336fed8fce040
Reviewed-on: https://gerrit.instructure.com/22234
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
Reviewed-by: Derek DeVries <ff87a0776152510efd53bb1f4ea089dbbc90e730@instructure.com>
Product-Review: Ryan Florence <2d8900489f91ac272fd9ce9d5789db6522668ca2@instructure.com>
QA-Review: Ryan Florence <2d8900489f91ac272fd9ce9d5789db6522668ca2@instructure.com>

roxolan/canvas-lms,djbender/canvas-lms,roxolan/canvas-lms,tgroshon/canvas-lms,Unow/canvas-lms,Rvor/canvas-lms,narigone/canvas,whalejasmine/canvas-lms,instructure/canvas-lms,grahamb/canvas-lms,matematikk-mooc/canvas-lms,HotChalk/canvas-lms,ShreniiNepal/shrenii_lmp,Jyaasa/canvas-lms,redconfetti/canvas-lms,djbender/canvas-lms,landonwilkins/canvas-lms,AndranikMarkosyan/lms,dgynn/canvas-lms,landonwilkins/canvas-lms,matematikk-mooc/canvas-lms,HotChalk/canvas-lms,wrdsb/canvas-lms,kyroskoh/canvas-lms,leftplusrightllc/canvas-lms,ShreniiNepal/shrenii_lmp,antoniuslin/canvas-lms,arrivu/jigsaw-lms,tgroshon/canvas-lms,jay3126/canvas-lms,arrivu/qibla-ecampus,wye0220/shindig-canvas,jay3126/canvas-lms,arrivu/hoodemo,SwinburneOnline/canvas-lms,arrivu/arrivu-lms,samuels410/greatlakes-lms,fronteerio/canvas-lms,shidao-fm/canvas-lms,instructure/canvas-lms,arrivu/qibla-ecampus,instructure/canvas-lms,juoni/canvas-lms,redconfetti/canvas-lms,AndranikMarkosyan/lms,usmschuck/canvas,jay3126/canvas-lms,gbleydon/canvas-lms,roxolan/canvas-lms,usmschuck/canvas,instructure/canvas-lms,samuels410/greatlakes-lms,Jyaasa/canvas-lms,va7map/canvas-lms,arrivu/jigsaw-lms,fronteerio/canvas-lms,wrdsb/canvas-lms,sfu/canvas-lms,dgynn/canvas-lms,sfu/canvas-lms,Rvor/canvas-lms,va7map/canvas-lms,arrivu/arrivu-lms,SwinburneOnline/canvas-lms,greyhwndz/canvas-lms,narigone/canvas,juoni/canvas-lms,antoniuslin/canvas-lms,grahamb/canvas-lms,va7map/canvas-lms,tgroshon/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,greyhwndz/canvas-lms,whalejasmine/canvas-lms,loganrun/pincan,utkarshx/canvas-lms,ShreniiNepal/shrenii_lmp,ShreniiNepal/shrenii_lmp,efrj/canvas-lms,Unow/canvas-lms,juoni/canvas-lms,skmezanul/canvas-lms,gbleydon/canvas-lms,dgynn/canvas-lms,instructure/canvas-lms,kyroskoh/canvas-lms,merichar/canvas-lms,grahamb/canvas-lms,utkarshx/canvas-lms,instructure/canvas-lms,samuels410/greatlakes-lms,sfu/canvas-lms,Unow/canvas-lms,landonwilkins/canvas-lms,whalejasmine/canvas-lms,matematikk-mooc/canvas-lms,eCNAP/CANVAS,djbender/canvas-lms,jay3126/canvas-lms,AndranikMarkosyan/lms,snehakachroo1/LSI_replica,grahamb/canvas-lms,shidao-fm/canvas-lms,sfu/canvas-lms,wrdsb/canvas-lms,sfu/canvas-lms,wimemx/Canvas,HotChalk/canvas-lms,kyroskoh/canvas-lms,eCNAP/CANVAS,tgroshon/canvas-lms,arrivu/hoodemo,snehakachroo1/LSI_replica,greyhwndz/canvas-lms,wimemx/Canvas,kyroskoh/canvas-lms,wye0220/shindig-canvas,Jyaasa/canvas-lms,samuels410/greatlakes-lms,eCNAP/CANVAS,arrivu/qibla-ecampus,greyhwndz/canvas-lms,matematikk-mooc/canvas-lms,skmezanul/canvas-lms,HotChalk/canvas-lms,redconfetti/canvas-lms,antoniuslin/canvas-lms,dgynn/canvas-lms,wye0220/shindig-canvas,venturehive/canvas-lms,gbleydon/canvas-lms,AndranikMarkosyan/lms,eCNAP/CANVAS,whalejasmine/canvas-lms,venturehive/canvas-lms,roxolan/canvas-lms,arrivu/arrivu-lms,narigone/canvas,juoni/canvas-lms,efrj/canvas-lms,djbender/canvas-lms,efrj/canvas-lms,leftplusrightllc/canvas-lms,leftplusrightllc/canvas-lms,shidao-fm/canvas-lms,snehakachroo1/LSI_replica,wrdsb/canvas-lms,fronteerio/canvas-lms,shidao-fm/canvas-lms,narigone/canvas,arrivu/jigsaw-lms,utkarshx/canvas-lms,usmschuck/canvas,snehakachroo1/LSI_replica,antoniuslin/canvas-lms,sdeleon28/canvas-lms,venturehive/canvas-lms,skmezanul/canvas-lms,SwinburneOnline/canvas-lms,utkarshx/canvas-lms,Jyaasa/canvas-lms,landonwilkins/canvas-lms,merichar/canvas-lms,sfu/canvas-lms,sdeleon28/canvas-lms,Rvor/canvas-lms,leftplusrightllc/canvas-lms,wimemx/Canvas,arrivu/hoodemo,SwinburneOnline/canvas-lms,va7map/canvas-lms,merichar/canvas-lms,redconfetti/canvas-lms,efrj/canvas-lms,instructure/canvas-lms,loganrun/pincan,sdeleon28/canvas-lms,grahamb/canvas-lms,loganrun/pincan,sdeleon28/canvas-lms,fronteerio/canvas-lms,usmschuck/canvas,skmezanul/canvas-lms,Rvor/canvas-lms