add note about Wagtail <=1.4 syntax for search_fields
add note about Wagtail <=1.4 syntax for search_fields

zerolab/wagtail,nealtodd/wagtail,kurtw/wagtail,wagtail/wagtail,Toshakins/wagtail,kaedroho/wagtail,takeflight/wagtail,jnns/wagtail,FlipperPA/wagtail,nilnvoid/wagtail,nutztherookie/wagtail,takeflight/wagtail,rsalmaso/wagtail,kaedroho/wagtail,FlipperPA/wagtail,mikedingjan/wagtail,nutztherookie/wagtail,thenewguy/wagtail,timorieber/wagtail,jnns/wagtail,kurtrwall/wagtail,iansprice/wagtail,nilnvoid/wagtail,nimasmi/wagtail,wagtail/wagtail,kurtrwall/wagtail,timorieber/wagtail,iansprice/wagtail,FlipperPA/wagtail,zerolab/wagtail,gasman/wagtail,Toshakins/wagtail,mikedingjan/wagtail,rsalmaso/wagtail,jnns/wagtail,mixxorz/wagtail,kaedroho/wagtail,iansprice/wagtail,zerolab/wagtail,Toshakins/wagtail,quru/wagtail,chrxr/wagtail,iansprice/wagtail,thenewguy/wagtail,rsalmaso/wagtail,nealtodd/wagtail,kurtrwall/wagtail,torchbox/wagtail,takeflight/wagtail,nilnvoid/wagtail,nutztherookie/wagtail,zerolab/wagtail,wagtail/wagtail,mikedingjan/wagtail,nutztherookie/wagtail,takeflight/wagtail,Toshakins/wagtail,mixxorz/wagtail,thenewguy/wagtail,rsalmaso/wagtail,thenewguy/wagtail,kurtrwall/wagtail,wagtail/wagtail,nimasmi/wagtail,gasman/wagtail,quru/wagtail,torchbox/wagtail,timorieber/wagtail,mixxorz/wagtail,kurtw/wagtail,wagtail/wagtail,kaedroho/wagtail,kaedroho/wagtail,zerolab/wagtail,gasman/wagtail,nilnvoid/wagtail,rsalmaso/wagtail,quru/wagtail,thenewguy/wagtail,kurtw/wagtail,FlipperPA/wagtail,nealtodd/wagtail,quru/wagtail,timorieber/wagtail,kurtw/wagtail,nealtodd/wagtail,chrxr/wagtail,mikedingjan/wagtail,chrxr/wagtail,torchbox/wagtail,nimasmi/wagtail,mixxorz/wagtail,torchbox/wagtail,gasman/wagtail,mixxorz/wagtail,nimasmi/wagtail,chrxr/wagtail,gasman/wagtail,jnns/wagtail