Disposition of comments for Media Queries CR

Proposed changes:

   http://www.w3.org/TR/css3-mediaqueries/#device-aspect-ratio

   # In this specification, aspect ratio is defined as the number of
   # horizontal pixels over the number of vertical pixels.

   change to

   | In this specification, aspect ratio is defined as the horizontal
   | length of the device's display divided by its vertical length.


   http://www.w3.org/TR/css3-mediaqueries/#resolution

   # The 'resolution' media feature describes the resolution of the
   # output device, i.e. the density of the pixels.

   Add

   | When querying devices with non-square pixels, in 'min-resolution'
   | queries the least-dense dimension must be compared to the specified
   | value and in 'max-resolution' queries the most-dense dimensions must
   | be compared instead. A fixed 'resolution' query never matches a device
   | with non-square pixels.

   (Alternatively we could allow two values to query each dimension
   independently, but I don't think this is useful.)

'not' and unknown media types:

Section 3 says: "The presence of the keyword 'not' at the beginning of the
query negates the results."  Section 4 says: "Media queries involving
unknown media types are always false".

When I read that, the word 'always' led me to wonder whether or not unknown
media types trump the section 3 definition of 'not'.  I suggest the
following clarifications:

1) remove the word "always" from the section 4 statement
2) Add an example showing that the following media query is true:

     @media not 3d-glasses { ... }

it'd be nice if we defined the lack of a media query string to mean "all"

Parsing is not well defined in terms of whitespace and error handling.

grid doesn't apply to all media

http://dev.w3.org/csswg/css3-mediaqueries/#media1 says:
  # For a media feature feature, (feature) will evaluate to true if
  # (feature:x) will evaluate to true for a value x other than zero.
 
Does this mean:
 
  (a) (width) is always true, even if the viewport width is zero,
  because "0px" is a value other than zero, or:
 
  (b) (width) is false when the viewport width is zero because "0px"
  and "0" are both not "other than zero"?
 
I'd also note that because specified widths cannot be negative,
(max-width) currently behaves the same as (width), whereas
(min-width) is always true.  Is that really intended?

After reading http://dev.w3.org/csswg/css3-mediaqueries/#grid it's
not clear to me whether the queries "(grid: -1)" or "(grid: 2)"
should be parse errors or should always be false.  It should be
clear.