Add pipe example

examples/src/pipe.cpp

@@ -0,0 +1,12 @@
+#include <utempl/utils.hpp>
+
+auto main() -> int {
+  using namespace utempl;
+  constexpr TupleLike auto tuple = Tuple{1, 2, 3, 4, 5, 6}
+    | Take<5>()
+    | Map([](int arg){return arg + 1;})
+    | Map([](int arg) -> float {return arg;})
+    | Reverse()
+    | Take<3>(); // Lazy evaluate
+  static_assert(tuple == Tuple{6.0f, 5.0f, 4.0f});
+};