Parse SUCC | LET | CASE | FN
Parse and lex data decl, two param func calls, prod types, unit
Split tests out into Test structure
Handle consecutive dedents
Refactor getIndentDedentTokens
Handle lexing name at eof
Refactor lexing dedent/indent still doesn't handle empty lines correctly
consumeNewlines and fixup
Print lexing error msg, don't allow indentifiers starting with numberic character
Lex explicit newline tokens
Lex IF | THEN | ELSE | DATA | BAR | CASE | COMMA
First lexing regression test and eatKeywordOrName