add virtual destructors to some of the interfaces
fix some unused variable warning in pvr.hts
fix some unused variable warnings in pvr.mediaportal.tvserver
fix some unused variable warnings in pvr.nextpvr
removed two unused methods in pvr.njoy
removed unused variable from pvr.vdr.vnsi
fix some unused variable warnings in pvr.wmc
use correct type when comparing to npos
use correct sprintf() specifiers
initialize variable inside loops to silence some warnings
remove pointless check
use const char* to avoid some warnings
use std::string instead of CStdString to avoid a comparison warning