test to see if the glue height is great then the main height

this is done as the spine wrapper it's self can have a value the same as
the document it's self due to the height:100%.  Simply removing that
will not solve the issue.  Since everything is measured based on the
glue element, this is where we will make the measure needed
By default the spine should be absolute positioning

we are only needing to force fixed positioning if the nav needs to move
with the scroll, other wise it doesn't need to be fixed as the scroll is
based on the navs height.  This will cover both a cropped spine and
overly link navs