wrong path for windows "to run" instructions

To compile (Windows):

```
cd [project folder]
dir /b /s *.java>sources.txt
md classes
javac -d classes @sources.txt
del sources.txt

To run:

cd [project folder]
java -cp bin com.theaigames.fourinarow.FourInARow [your bot1] [your bot2] 2>err.txt 1>out.txt
```

note the path difference - classes vs. bin
