Backport TSFE getHash hook to TYPO3 CMS 4.5
Within TYPO3 CMS 4.5 it is not possible for the contexts extension to modify the cache hash since a submitted cHash (e.g. via $_GET) is required to do so.
This was fixed with TYPO3 CMS 4.7 in #28299 but was not backported to 4.5. This extension could provide that backport since it adds a XCLASS for