* ./src/libvlc.c, ./include/main.h: the root of all objects is now
p_libvlc, and each p_vlc is a child of p_libvlc. Reasons for this are: o the module bank and the message bank only need to be initialized once, which gives faster loads when multiple instances of libvlc are used, o we allow the possibility of different p_vlc sharing objects, for instance the audio output, o the CPU detection is only done once. This patch is not polished yet, but I cannot do any intensive tests for the moment because of a bug somewhere that leaves audio output objects lying here and there which needs to be investigated first. The current major issue is that the module bank is no longer freed.