Here is the starting point. All the source are from Mr.Kwak.
I need to work on from here.
Refactored tozzy.go: easier to read
Deleted some fmt.Println: just used for debugging
nothing special: just working around to understand and find the bug.
Two problems are temporarily solved.
	1. deadlock
	2. infinite loop
I sent an E-mail to Mr.Kwak, waiting for the response.
After the response, I will work on it more.
properly added some error check for the 'itemError' type in lexerTest() in parse.go.
The program terminates when it encounters an error before seeing the right delimiter.
And it should print that it met an lexing error rather than printing "DONE FOR NOW",
because "DONE FOR NOW" means that it completed lexing.
Added 'println' statements to figure out the code flow in parse.go and lex.go.
I tried to follow all the code flow because i couldn't understand what this code means,
but I gave up figuring out everything in detail.
Now I stop here and am going to fix the lex error only, without understanding the whole code flow.
Fixed the lexer bug. Before, it had some bugs with lexing.
For example, it didn't recongnize "*" and it reported error with "10.nil"(bad number)

Now, the lexer recognizes "10", ".", and "nil" respectively instead of reporting error with "10.nil".
The log prints "DONE FOR NOW" after lexerTest().
This means the lexer works well.