fix unused variable warnings in pvr.argustv
fix unused variable warnings in pvr.demo
add virtual destructors to some of the interfaces
fix unused variable warnings in pvr.dvblink
fix unused variable warnings in pvr.hts
fix unused variable warnings in pvr.mediaportal.tvserver
fix unused variable warnings in pvr.nextpvr
fix unused variable warnings in pvr.njoy
fix unused variable warnings in pvr.vdr.vnsi
fix unused variable warnings in pvr.vuplus
fix 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 CStdString instead of char* to avoid some warnings
use std::string instead of CStdString to avoid a comparison warning