vasm.py: Add BYTE; Highlight errors on TTY
vasm.py: Add BYTE; Highlight errors on TTY

kervinck/gigatron-rom,kervinck/gigatron-rom,kervinck/gigatron-rom,kervinck/gigatron-rom,kervinck/gigatron-rom,kervinck/gigatron-rom,kervinck/gigatron-rom