arv-tool: help tweaks.
arv-tool: help tweaks.

AravisProject/aravis,AravisProject/aravis,lu-zero/aravis,AnilRamachandran/aravis,AravisProject/aravis,lu-zero/aravis,AravisProject/aravis,lu-zero/aravis,lu-zero/aravis,AnilRamachandran/aravis,AnilRamachandran/aravis,AnilRamachandran/aravis,lu-zero/aravis,AnilRamachandran/aravis,AravisProject/aravis