Column headers in User search should have descriptive text added

[Jono M]

In Administration -> Users -> User search, results are displayed in a table with profile pictures in the first column. However, the column header for this column is blank - it should be changed to contain hidden "Profile picture" text so that screen reader users know what the column contains.
Also, the final column header contains links to select all / deselect. These should be moved to the bottom of the column (like in Inbox) and a descriptive column header should be added.

Affects latest master

[Robert Lyon (robertl-9)]

Moving 'all/none' here not as useful as in inbox as the list can get quite long and so is more useful to have the 'all/none' at top.

So only the adding of column headers is needed

[Mahara Bot (dev-mahara)]

Patch for "master" branch: https://reviews.mahara.org/3386

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/3386
Committed: http://gitorious.org/mahara/mahara/commit/4369ffed72c64be7ac115d9cc62188bbdee10ba6
Submitter: Yuliya Bozhko (<email address hidden>)
Branch: master

commit 4369ffed72c64be7ac115d9cc62188bbdee10ba6
Author: Robert Lyon <email address hidden>
Date: Wed May 28 08:31:36 2014 +1200

Adding accessible text to column headers in users -> search (Bug #1266924)

Adding accessible text to:
- the profile icon column
- the select users checkbox column

Change-Id: I663478e05588bdd3d34ab2995465d6bbf7ba3359
Signed-off-by: Robert Lyon <email address hidden>