[NTVDM]

[NTVDM]
- Implement INT 10h, AH=13h "Write String" function.
- Fix VidBiosPrintCharacter to use the colour attribute only in graphics mode, or when explicitely needed.
- Fix some special cases where specifying a BIOS mode page of 0xFF means "use current page".
- Use a macro to check whether a given mode number specifies a text mode, and use it where needed.

svn path=/trunk/; revision=68347