Fixing CSS feature detection and CSS properties.

We use -webkit, -moz and bare properties everywhere. In the near future we can
probably ditch the -webkit/-moz versions.
Adding charset to fix difference between framed and non-framed versions.

The character encoding of a framed document was not declared. The document may
appear different if viewed without the document framing it.
Disabling test-dynamic-load as it needs "relative_at" to work reliably.
Skip empty string.
Round generated values to 4 significant figures.

(and deal with very small numbers).
Only test for 4 significant figures when checking styles.
Regenerate auto-test-composite-transform's checks file.
Put the search string in the src box to make testing quicker.
Output for checks file now use one at() per time.
Temp.