Java define return types

[alexp141]

Added ability to define return types in Java more easily when creating a function. Previously, the return types would always default to void. Now, you can (optionally) decide to specify the return type of a function during creation. The previous way of defining functions still works too.

Example: saying "pub static String funky my function" will return
public static String myFunction()

This works for all of the code types defined in java.py

[alexp141]

Just realized that this breaks every language that uses the code_functions tag that isn't Java. Will update if I come up with another solution.

[alexp141]

I have finished testing this and it looks like it works well.

Some final thoughts: There are two main ways I thought of doing this. The first way is the way that I did it in my first commit which involved changing all the code_* functions in functions.py to allow them to accept return values as arguments and the way that I did it in my last commit where the correct function is chosen based on whether the user dictates a return type or not. Both ways have pros and cons.

I also wanted to add that even though I only did these changes for Java, the same thing could be done for other languages as well.

Any feedback is appreciated!