File_Structure_Test to make sure we don't regress.
According to the PHP docs, the "public" keyword is implied on static
functions, so remove it. Also, require private static functions to
start with an _.
http://php.net/manual/en/language.oop5.visibility.php
this to show a "your thumbs/resizes are out of date" message whenever
we change the graphics rules. Tweak watermark module to add graphics
rules whenever we make a change, which triggers the graphics module to
add the permanent message.
1) they now have their own matching severity constants
2) they both have convenience functions success(), info(), warning() and error()
3) they both have severity_class()
