Add clearing cache by tag and by identifier to t3lib_tcemain->clear_cacheCmd()
The caching framework supports to remove cache entries by identifier and by id. If this was supported by the t3lib_tcemain->clear_cacheCmd(), this feature could also be used in TSConfig's TCEMAIN.clearCacheCmd.
As both require an additional parameter I suggest a syntax like this:
TCEMAIN.clearCacheCmd = tag:firsttag,tag:secondtag
TCEMAIN.clearCacheCmd = id:first,id:anotherid
Of course this still can be combined and also used with the other features:
TCEMAIN.clearCacheCmd = 15,tag:news,id:latestnewsbox