fix #1211: for table-related elements, handle temporarily as 'block' display intead of 'inline' display
auto merge of #1216 : june0cho/servo/temp_fix_tableflow, r=kmcallister

In order to fix the wikipedia error, I temporarily change the display property of table-related elements to 'block' instead of 'inline'.
When table is implemented, it should be changed to proper value.

@sonwow
@brson