Remove horizontal/vertical label alignment for parallels/meridians in draw_graticule method of LayeredBasemap to solve ugly label alignment in newer versions of Basemap.

git-svn-id: https://svn.seismo.oma.be/svn/seismo/mapping/layeredbasemap/trunk@6892 40b490c5-b4d9-47cb-8714-9bef99b524d5