added pair declaration in its own file
fixed extract_parentheses() comment
added string_copy() to parse_tree utils
replaced ~ with dagger symbol
used different replacers and added three new functions in sanitizer
handled crazy error in extract_parentheses()
refactored create_tree (pretty much rewrote it) and other stuff in parse_tree
added pair.c and sanitizer.c in makefile
main.c now runs pretty well
add phrases file for demo