Stop error when we find a now-deleted user in the history
tidy up task board templates
tidy up milestone board topbar and add close button
tidy up milestone board template
remove close milestone checkbox, start a dedicated close page
switch milestone view to using i18n
consolidate milestone topbars
icebox as droppable list
add header text for close milestone page
add a close link to the milestone overview
Fix #284 Glowy border around sprint board drop targets while dragging
Fully-working milestone close/reopen functionality