init
Implemented rune scanner goroutine and defined token types
Lexer: Implemented indentation/dedentation token
Started implementation of rest of tokens, need to refactor
Removed lexer implementation, starting a rewrite
Need to rethink constants
State-function-based lexer, no lexing functions implemented yet
lexIndent(), lexIdentifier(), lexSpace() --- untested
Switched back to bufio.Scanner (line-by-line).  Implemented lexIndent
Implemented the rest of the lexing state functions
Bug fixes, correctly parses sample.lang
parse.go
Need to modularize parse.go:
 - separate method for each non-terminal
 - pass around sub-trees rather than keeping global pointer in *parse object
parseStmt() implemented
parseLabel, parseFunc_def, parseBlock
parseIf_stmt, parseParam
parseAssign_stmt
parseReassign_stmt
parseJump_stmt, parseReturn_stmt, parseExpr, parseFunc_call
started debugging parse.go