add fibonacci recursive

[ntua-el20199]

No description provided.

[kostis]

Thanks for your contribution.

Since this program already exists for other languages (e.g. alan/programs/fibonacci.alan), for uniform testing it's better that it takes its input without any printing of a prompt (i.e. without "Enter a number") and outputting its result in the same way as the corresponding Alan program. Then we can simply add symbolic links to the corresponding input & result files in the Alan dir.

Please do these changes and I will merge this.

[ntua-el20199]

I believe it should now comply with the alan Fibonacci input/output