VHDL tutorial

To be added: a tutorial on VHDL design with a design example (likely the DAC emulator). Also to be included: the VHDL resolution table:

VHDL Resolution Table

	U	X	0	1	Z	W	L	H	-
U	U	U	U	U	U	U	U	U
U	X	X	X	X	X	X	X	X
U	X	0	X	0	0	0	0	X
U	X	X	1	1	1	1	1	X
U	X	0	1	Z	W	L	H	X
U	X	0	1	W	W	W	W	X
U	X	0	1	L	W	L	W	X
U	X	0	1	H	W	W	H	X
U	X	X	X	X	X	X	X	X