Test cases

Test cases for the following issues
[issue #45](http://sourceforge.net/p/cssbox/bugs/45/)
[issue #49](http://sourceforge.net/p/cssbox/bugs/49/)
[issue #51](http://sourceforge.net/p/cssbox/bugs/51/)
[issue #52](http://sourceforge.net/p/cssbox/bugs/52/)  `[FAILS]`
[issue #55](http://sourceforge.net/p/cssbox/bugs/55/)
[issue #56](http://sourceforge.net/p/cssbox/bugs/56/)  `[FAILS]`
[issue #57](http://sourceforge.net/p/cssbox/bugs/57/)