Added zoom buttons

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@10842 e0a1b77d-ad91-4216-81b1-defd5f83fa92
Added zoom buttons

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@10843 e0a1b77d-ad91-4216-81b1-defd5f83fa92