Word Break Run Rounding

Tests for http://bugs.webkit.org/show_bug.cgi?id=13438 Run rounding makes word-break:break-all/word not functional.

Test that the preferred (maximum) width is right:

The black border should fit tightly around this one line of text with no space after the period.

Test that text does not wrap too early due to rounding errors:

This text fits nicely on a single line of the given width.

Test that text does not wrap too late:

J u s t a b u n c h o f l e t t e r s h e r e , n o t h i n g t o s e e . Thisisonebigwordwhichisverylong.