update readme. Laverna#1

Author: filtercake

test/visual/README.md

@@ -1 +1,19 @@
-        $ ./node_modules/casperjs/bin/casperjs test test/visual/testsuite.js
+is wip.
+
+`npm install` should install all dependencies: phantomjs, casperjs and phantomcss. (if you haven't had laverna running before, also do `bower install`.)
+
+then run
+
+        $ ./node_modules/casperjs/bin/casperjs test test/visual/testsuite.js
+
+to make reference screenshots. run again to see tests passing against them.
+
+run `grunt serve`, add some css for `#header-title` at the end of `styles/theme-default/theme-default.less`, then run again to see tests fail.
+
+also, the failure screenshots show up as untracked files in `git status`.
+
+
+next steps:
+
+- https://github.com/chrisgladd/grunt-phantomcss
+- set up grunt task to clean up after green tests