Major new spec changes

- Wildcards are represented by a tilde ( ~ )
- Hunks are separated by spaces, not commas
- Margins have been removed. Guides can be snapped to edges using
wildcards.
- "Position" option has been removed.
- "Origin" option has been added, takes over position option syntax.
- Offset option has been added
- Options are specified in parens after a grid. Width and offset are
added as paramaters, after commas.
- Guides are added via guide hunks represented by pipes ( | ). Unit
hunks advance the insertion point.