add parser
add variableset.variable
add parser2
move parser2 -> parser
update parser
add parens parsing
add recursion pass down variableset, add parser debug arg
rewrite tokenize to use transitions, fix parse pass down debug variable
fix tokenizer parens and adjancency multiplication
add AssertionError exception type to test_frame
add integrals to tokenize, add tokenizer tests
add integrals to parse
add power to tokenizer and parser, fail tokenizer on unknown char
add demo-able (sortof) example
add Fraction Expression
add talking example
demo on 5/30
reimplement and comment VariableSet