Updated field class to use doubleborder mixin
fixed undefined offset #2276
Minor bug fix to show link description field 

When adding a link, the description field was present, but hidden. Adjusted javascript to show the description field
Fix misleading documentation about Children.max

Currently, the documentation implies that doing a `Children.max(LastEdited)` will work, which isn't the case.
This change uses `AllChildren.max(LastEdited)` instead, which while slightly more inefficient, will actually work consistently.
Merge pull request #2279 from ss23/patch-7

Fix misleading documentation about Children.max in partial caching
FIX: pass controller as reference inside closure.

Non referenced causes segfaults on PHP <= 5.3.8 environments when opening subtrees in the CMS. Likely the cause of silverstripe-cms/issues/803.
Changelog note on form method limitations

See 14c59be85e9ec53cb2f0b3e9d0d8ce7569d913c6.
Raised by Fara Rustein of Deloitte Argentina (CVE-2013-2653).
Merge pull request #2284 from wilr/closure_this_reference_fix

FIX: pass controller as reference inside closure.
Merge pull request #2278 from jonshutt/patch-1

Minor bug fix to show link description field
Merge pull request #2277 from joernroeder/3.1

fixed undefined offset #2276
Docs: Consistent arg quoting in <% require %> (#1614)
Merge pull request #2271 from ARNHOE/3.1-twotoneborders

Updated field class to use doubleborder mixin
Merge remote-tracking branch 'origin/3.1'