Try to solve alternative services craziness

The current service was checked on the group (alternative list) instead of
the real selected and played service.

Thanks Dima73 for finding this craziness what was in our code for a long
time
servicemp3: Don't log subtitle data. Don't alloc on stack.

Subtitle data may be binary image data (e.g. VOB subs). Do not log them
on the console as plain text.

Allocating memory from the stack is bad - the stack will never shrink back.
Use new/delete to allocate a 128k buffer.
servicemp3: Fix init order warning. Allow binary storage in subtitle data.

Fix compiler warning about member initialization order.

Store subtitle data directly into std::string, thus allowing these
to contain binary data (in particular, \0 characters).
Merge remote-tracking branch 'pli/master'

Conflicts:
	lib/service/servicemp3.cpp