[YABI-552] Select multiple files in YABI to delete

[ccgbuildbot]

[reporter="pmoolhuijzen", created="Mon, 16 Mar 2015 10:32:11 +0800"]

Reporter: This is a request from a Curtin User.

Component: Yabi Files Web Interface
Options: 'Select and delete multiple individual files'
Request: Can the user in files tab select multiple files to delete?

I assume they don't want to recursively delete all the contents of directories. (Will double check)