Add SpectreElementAttributeInt

Signed-off-by: John McCutchan <john@johnmccutchan.com>
Semi-working <s-texture> tag.

Signed-off-by: John McCutchan <john@johnmccutchan.com>
Example of <s-texture> tag with color attribute.

Signed-off-by: John McCutchan <john@johnmccutchan.com>