With channelnumber change now drive a evStart event

By making that function public in pcore.h it is available in python
Can also be used after renaming services.
ChannelSelection: Add remove all cable and all teristical services

As discussed here: http://openpli.org/forums/topic/34637-kabel-verwijderen-uit-satelliet-lijst/
Add confirmation before delete whole satellite/cable/terristical channels
Finetuning around remove whole satellite/cable/terristical services
encoder: add support to query the number of encoders which are in use
export eEncoder::getUsedEncoderCount to python
Merge branch 'master' of git://git.code.sf.net/p/openpli/enigma2 into BETA