BUGFIX: 7117 Fixes

Includes:
* Changes to chosen to include a custom function that will let the
drop-down rise-up if there is room and it would otherwise drop beneath
the size of the window (changes in coffeescript, jquery output, and
chosen css)
* Changes in SCSS to stop the automatic addition of scrollbars, and
to limit the extra space at the bottom of the filter div

Issues remaining:
* jLayout is calculating the height of the filter div incorrectly.
It is assuming the div is around 70px longer than it is. This height
assumption is linked somehow to chosen, as initiating the select box
results in a correct height calculation.
ENHANCEMENT: Add disabled state to preview buttons and add watermark for the current state being viewed (TRAC:7214)
ENHANCEMENT: Style change to buttons for preview states. Removed open in new window (TRAC-7214)
BUGFIX Don't' set 'Referer' header in FunctionalTest->get()/post() if its explicitly passed to the method
SECURITY Return true for Director::is_absolute_url() checks if they're prefixed with two or more slashes (as browsers interpret this as a valid URL)
SECURITY More solid URL checks in Director::is_site_url(), using a conservative parse_url() hostname comparison rather than Director::makeRelative(), which is not designed for security purposes
BUGFIX: updating the value of a tree dropdown field, its title is not updated accordingly if using TreeTitle as the drropdown item title
ENHANCEMENT SQLQuery::selectField() returns a SQLQuery object to be
consistent with how the other add/set methods work.
MINOR Fixing DbDatetimeTest to use the correct selectField to select an
alias
MINOR Tidy up of SQLQuery constructor docs and default args, limit is
stored internally as an array, not a string.
MINOR SQLQuery doc cleanup
Merge pull request #409 from normann/sapphire

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Add page icons to the tree node in TreeDropdownField in page add form.
Merge pull request #386 from adrexia/sapphire

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Includes:
* Changes to chosen to include a custom function that will let the drop-down rise-up if there is room and it would otherwise drop beneath the size of the window (changes in coffeescript, jquery output, and chosen css)
* Changes in SCSS to stop the automatic addition of scrollbars, and to limit the extra space at the bottom of the filter div

Issues remaining:
* jLayout is calculating the height of the filter div incorrectly. It is assuming the div is around 70px longer than it is. This height assumption is linked somehow to chosen, as initiating the select box results in a correct height calculation.
Merge pull request #402 from ohararyan/sapphire

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http://open.silverstripe.org/ticket/7214

Added watermark to show current state of preview.
Removed button styling from Draft and Preview and added styling to show current selected state.

Designs signed off by Paul

Conflicts:
	admin/css/screen.css
MINOR Tree metadata naming
MINOR: Fix coding conventions
MINOR Fixed style sprites broken by pull request #402
MINOR Reverting padding changes from pull request #377, way too global - solved through a .cms-panel-padded class in CMSSettingsController instead
Merge pull request #411 from ajoneil/blowfish

MINOR: Fix coding conventions
Merge pull request #401 from chillu/is-absolute-url

Director::is_absolute_url() security fixes
MINOR Updated TinyMCE dependency from 3.4.6 to 3.5
ENHANCEMENT addExtraClass() support for Tab and TabSet