[FEATURE] Backport TSFE createHashBase hook to TYPO3 CMS 4.5

Fixes http://forge.typo3.org/issues/56269
TYPOC-89: update changelog
TYPOC-75: GET parameters get appended to all URLs even when they are stored in session
TYPOC-74: contexts is compatible with 4.5 now
TYPOC-88: Prettify contexts list in TCA (page/content records)
TYPOC-88: Show message when no contexts defined
TYPOC-90: release 0.4.0