samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/fib2.t

@@ -0,0 +1,27 @@
+local test = require("test")
+
+local Num = int
+
+terra fib(a : Num) : Num
+    if a == 0 then
+        return 1
+    elseif a == 1 then
+        return 1
+    else
+        return fib(a - 1) + fib(a - 2)
+    end
+end
+
+function fib2(a) 
+    if a == 0 then
+        return 1
+    elseif a == 1 then
+        return 1
+    else
+        return fib2(a - 1) + fib2(a - 2)
+    end
+end
+for i = 0,10 do
+    print(fib(i))
+    test.eq(fib(i),fib2(i))
+end