v<1.0>, <06/08/2014> -- Initial release.
v<1.1>, <06/08/2014> -- Bug Fix.
v<1.2>, <15/08/2014> -- Rewritten using built-in XML libraries, and is more compliant with XES standards.
v<1.3>, <29/04/2015> -- Updated with changes by github users mdiro and ekaats, and questions by Hudan Studiawan. Added a for loop in Traces.build_trace() and nested attributes. 
