erlang-p1-stringprep: bump to version 1.0.0

This version includes C++ code, so also add dependency on a C++
compiler.

Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com>
[Thomas:
 - propagate new C++ dependency to ejabberd, as noticed by
   Romain Naour
 - fix license information and license files. Not all the code is
   under the TCL license, in fact most of the code is under the
   Apache-2.0 license, and some additional license files have been
   added to clarify this.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>