Ran test cases with test_classes enabled. Everything appeared to check
correctly.
Added new test cases to phreeqcpp/mytest.
Added zero.sed to examples and mytest.
git-svn-id: svn://136.177.114.72/svn_GW/phreeqcpp/trunk@1376 1feff8c3-07ed-0310-ac33-dd36852eb9cd
