Test input files are installed in the shared directory.
Initial XML parsing and RelaxNG validation.
Refactor AddParent/parent() methods for events.
Initial tree building while parsing XML input file.
Initial working analysis with XML files.

Added 'atleast' gate, which is the same as "Vote".
Incorporate checking uninitialized gates and probabilities.
Model-data section is handled.
Adjustment for first analysis of Baobab trees.