package/libdvbsi: new package

libdvbsi++ is a C++ library for parsing DVB SI sections and providing
the output in C++ objects. It's usefull in any case you need prepared
and preselected DVB SI data from the raw stream.

[Peter: fix _LICENSE_FILES tag]
Signed-off-by: Carsten Schoenert <c.schoenert@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>