Only test for 4 significant figures when checking styles.
Round generated values to 4 significant figures.

(and deal with very small numbers).
Removing expected failures for tests which now pass.
Regnerating a couple of -checks file with rounding.
Merge pull request #400 from mithro/rounding-fix

Change the test code to only check for 4 significant figures.
Update firefox before building.
Adding stable/beta/unstable versions for Firefox.