update webif streaming
eitd: remove unused FreesatTables.hpp
eitd: Reduce sectionsd memory requirements:

* Various EPG related strings (language- and country keys, audio
descriptions) come with a pretty low variance. Cache them, and use an
index instead of allocating redundant strings for each and every
SIevent.
* Storing content classifications in native format instead of
std::string removes quite some memory overhead, too.

This saves about 250 bytes of RAM for every event cached, resulting in a
considerably reduced sectionsd memory footprint.

Conflicts:
	src/eitd/xmlutil.cpp