Merge pull request #2088 from g4b0/cache-comments

Inline documentation updated
API Allow $summary_fields to support methods on DBFields
Fixed Tab floating in CMS (fixes #1778)

Removed inline-block from header elements which seems
to cause the issues of tabs stacking on top of each other.
Replaced header background to work on multiline scenarios
Added bottom margin to breadcrumbs so they don't look cramped
when tabs are floated below them.

See https://github.com/silverstripe/silverstripe-framework/pull/1863,
https://github.com/silverstripe/silverstripe-framework/issues/1943,
https://groups.google.com/forum/?fromgroups#!topic/silverstripe-dev/c-W-ZxDlDuA,
http://open.silverstripe.org/ticket/6882
AssetAdmin reset button and chosen.js (fixes #1640)

See https://github.com/harvesthq/chosen/issues/215
Merge pull request #2087 from tractorcow/3.1-summary-field

API Allow $summary_fields to support methods on DBFields
Always load preview when in preview mode, not in edit mode
Force TreeDropdown to remember selected title.
Merge pull request #2092 from robert-h-curry/tree-dropdown-unsticky-selection

Force TreeDropdown to remember selected title.
Merge pull request #2091 from robert-h-curry/cms-preview-not-loading

Always load preview when in preview mode, not in edit mode
Always load preview when in preview mode, not in edit mode
API New CMSForm class to allow validation responses in CMS (fixes #1777)

Thanks to @willmorgan for getting this discussion started
(see https://github.com/silverstripe/sapphire/pull/1814).
Consistent Form setters (returning $this on setHTMLID())
Replace DataObject->isNotNull() helper with closure

Now possible since we support PHP 5.3+ only.
TinyMCE "Insert Media" screen, update button triggers navigation (fixes #742)
Note about IE10 support
Removed "Last visited" from admin/myprofile (fixes #648)

It doesn't make any sense in this context
LeftAndMain.js: Fix 'X-Reload' for IE10 (fixes #647)
BUG Resize infinite loops in IE8 (fixes #575)

IE8 gets a bit confused and fires resize events
when element dimensions in the DOM are changed
as a result of a resize event, causing an infinite loop.
Apart from artificially throttling the event, the only solution
I've found is to check for actual window dimension changes.
http://stackoverflow.com/questions/12366315/window-resize-event-continually-fires-in-ie7?lq=1

This implicitly fixes an issue where TreeDropdownField panel isn't
accessible in the "Insert Media" popup, because the resize event happes
to be triggered by the popup overlay, and in effect closes the drop down
panel right after opening it.

Relating to the jQuery UI component, there's a host of issues and discussions around this, but no solution…
http://bugs.jquery.com/ticket/4097
http://bugs.jqueryui.com/ticket/4758
http://bugs.jqueryui.com/ticket/4065
http://bugs.jqueryui.com/ticket/7514
http://bugs.jqueryui.com/ticket/8881
https://groups.google.com/forum/?fromgroups#!topic/jquery-ui/fDSvwAKL6Go
http://www.mail-archive.com/jquery-ui@googlegroups.com/msg04839.html
Min/max constraints for CMS dialog
Merge pull request #2022 from willmorgan/patch-2

Allow canCreate to be extended via Object->extend