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
API CHANGE Removed Member_SignupEmail, use your own custom sign up Email class instead.
API CHANGE Deprecate Member::sendInfo(), use Member_ChangePasswordEmail and Member_ForgotPasswordEmail class directly instead.
FEATURE: add Levelup component to GridField as GridFieldLevelup
API CHANGE Deprecated internal access to SQLQuery properties, update core code to reflect these changes.
Using set/add instead in accessor methods, and use Database::sql*ToString() to allow easier per-database adapter SQL overloading.
APICHANGE: PasswordEncryptor::check() allows for more powerful password checking, deprecating PasswordEncryptor::compare()
ENHANCEMENT: Use the best blowfish encryption available - this fixes fragility between PHP versions and system installations
BUGFIX: Increase size of varchar fields on MemberPassword to match those defined in Member. This fixes issues when the password hash is longer than 50 characters, and was being truncated when saved in MemberPassword.
Merge pull request #400 from halkyon/sqlquery_enhancements

API CHANGE Deprecated internal access to SQLQuery properties
Merge pull request #408 from ajoneil/blowfish

Fix blowfish encryption
Merge pull request #407 from normann/trac/7173

trac 7173, Add "level up" list entry to CMS page list view
BUGFIX: updating the value of a tree dropdown field, its title is not updated accordingly if using TreeTitle as the drropdown item title
BUGFIX Ensure end bracket for HAVING clause is put in the right place
Merge pull request #405 from halkyon/member_changes2

API CHANGE Removed Member_SignupEmail and deprecate sendInfo() on Member
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.