Update README, new tests

tests/recursivefib.grnd

@@ -0,0 +1,24 @@
+fun !fib -int -int &n -function &fib
+    # Base case: fib(0) = 0, fib(1) = 1
+    lesser $n 2 &isBase
+    if $isBase %baseCase
+    
+    # Recursive case: fib(n) = fib(n-1) + fib(n-2)
+    subtract $n 1 &nMinus1
+    call !fib $nMinus1 $fib &fib1
+    
+    subtract $n 2 &nMinus2
+    call !fib $nMinus2 $fib &fib2
+    
+    add $fib1 $fib2 &result
+    return $result
+    
+    @baseCase
+    return $n
+endfun
+
+# Main program
+println "Computing fib(30) recursively..."
+call !fib 30 $fib &answer
+println "Result:" $answer
+end