gbx: make own cpu and api byte configurable. Optional parameter

	- Should be set automatically according to the function in the commented code
	- Similar to changeset 9642 for the version byte
	- Documentation change:
	oscam.conf
	[gbox]
	my_cpu_api = cpu and api byte in hex, default = 40
	example: my_cpu_api = 60



git-svn-id: http://streamboard.de.vu/svn/oscam/trunk@9706 4b0bc96b-bc66-0410-9d44-ebda105a78c1