Table fix

vmerge is the vertical class for rowspans. there is supposed to be an attribute val of 'continue' when rowspans are meant to be incremented. however, if a user manually merges cells, word will insert a vmerge element, with no attribute. from the open xml docx:

If this attribute is omitted, its value shall be assumed to be continue.

So in the utils file, we should be looking for the continue attrib, as well as a vmerge with no attrib