CommandText stuct change

[chwo...@gmail.com]

In the future we would like to support more text styles than just
italic. I think we should change the CommandText struct to reflect
this. We could either make a list of StyleType or we could create a
bitmask. I would prefer the bitmask myself. So we could define

#define NO_SYTLE 0x01
#define ITALIC 0x02
...

or maybe

typedef enum { nostyle = 0x01, italic = 0x02 ... } StyleType;

and then we could

txt->style &= italic;

When we could set the font style in execute.c based on this bitmask.