add notes about arrow selector changes
add notes about arrow selector changes

GerHobbelt/bootstrap,m5o/bootstrap,tjkohli/bootstrap,inway/bootstrap,zalog/bootstrap,peterblazejewicz/bootstrap,zalog/bootstrap,kvlsrg/bootstrap,inway/bootstrap,stanwmusic/bootstrap,stanwmusic/bootstrap,stanwmusic/bootstrap,GerHobbelt/bootstrap,kvlsrg/bootstrap,kvlsrg/bootstrap,stanwmusic/bootstrap,peterblazejewicz/bootstrap,twbs/bootstrap,m5o/bootstrap,peterblazejewicz/bootstrap,zalog/bootstrap,tjkohli/bootstrap,coliff/bootstrap,coliff/bootstrap,GerHobbelt/bootstrap,inway/bootstrap,twbs/bootstrap