Bulk edit/reserve/delete items

[obfuscoder]

From @obfuscoder on March 18, 2015 19:31

It should be possible to bulk-edit/delete/reserve items. This means a checkbox should appear before each item, if bulk edit is enabled. Also selections based on filter and select all/none, invert selection should be possible. After selecting one or more items, the options should become available to edit/delete them in bulk mode or - if a reservation for a specific event has been made - reserve those items (create labels for them).

Copied from original issue: obfuscoder/flee_cake#14