Changed way of instanization of class StreamLogger. Now it has a static newInstance() method which returns a reference. This way a user don't need to remember to always use "new" keyword.
Changed way of instanization of classes SimpleLogFormatter and XMLFormatter to use static newInstance(...) methods.
Updated tests to make use of new way of Loggers and Formatters instanizations.
Changed name of readme.mdown to readme.md
Changed behaviour of Makefile's rule 'clean': now it cleans only the library's files.
Added rule 'distclean' to Makefile. This allow to clean all, including dependancies.
Added basic includes to rlog.hpp header.