Add doxygen docstrings
Add Doxygen config file.
Add docs option to Makefile
Add recursive option to include ./datastructures
Refactoring of tree datastructure

Refactor symbols and names.
Add a tree_print function for debugging.
Rewrite language sample to be more lispy
Rewrite tree_print function to be more simple
Rewrite of the parser
Use strtok not strtok_r, fix malloc
Add error checking for invalid files
Fix errors allocating memory
Remove unnecessary casts
Refactor print method:wq
Ignore newlines, remove debug statements
Add function for adding children to a node
Move function to add children to a node to tree.c
Silence warnings
Remove unused variables
Reorganization of tests
Add tests for the tree