Tab character now moves to tabstop.

Now \t will move to the nearest 4-character-aligned column.

This relies on the fact that all VGA text mode widths are a multiple of 4, and so it's safe to perform this calculation on the offset rather than just the x-component of the offset.
Merge pull request #1 from AbigailBuccaneer/vga-tabstops

Tab character now moves to tabstop.