fix empty results for text_contains due to broken xpath selector (it should search the node itself not the text() node, cf http://stackoverflow.com/questions/3655549/xpath-containstext-some-string-doesnt-work-when-used-with-node-with-more
a better fix for broken xpath text_contains() selector that doesn't break the tests. includes more tests. @tomchristie/webdriverplus#29
Merge pull request #29 from craigds/master

fix text_contains