samples: add Terra samples

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

samples/Terra/bounce.t

@@ -0,0 +1,23 @@
+local io = terralib.includec("stdio.h")
+
+struct Count { value : int }
+function luafn(a)
+	print("lua:",a.value)
+	a.value = a.value + 1
+	terrafn(a)
+end
+terra terrafn(a : &Count)
+	io.printf("terra: %d\n",a.value)
+	if a.value < 100 then
+		luafn(a)
+	end
+	return a.value
+end
+
+terra begin()
+	var c = Count {0}
+	return terrafn(&c)
+end
+
+local test = require("test")
+test.eq(begin(),100)