[FEATURE] Add ucfirst to stdWrap

Extend stdWrap's "case" with "ucfirst" and "lcfirst" keywords to
convert the first letter of a sentence to the corresponding form
using the current Frontend character set.

Change-Id: Ic00989e662724c8a5bdd8c84a6ebdfce79d85319
Resolves: #28018
Reviewed-on: http://review.typo3.org/3171
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind
Reviewed-by: Jo Hasenau
Tested-by: Jo Hasenau
Reviewed-by: Xavier Perseguers
Tested-by: Xavier Perseguers