task: add hook for modifiying the tags to filter for ('modifyTagsAgainst').

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/ke_search/trunk@85801 735d13b6-9817-0410-8766-e36946ffe9aa
task: add hook for third party applications to manipulate last part of query building. Thanks to Bastian Bringenberg and Felix Jacobi, http://forge.typo3.org/issues/58285.

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/ke_search/trunk@85802 735d13b6-9817-0410-8766-e36946ffe9aa