Add tasks for all the new languages

Task/Y-combinator/Eero/y-combinator.eero

@@ -0,0 +1,29 @@
+#import <Foundation/Foundation.h>
+
+typedef int (^Func)(int)
+typedef Func (^FuncFunc)(Func)
+typedef Func (^RecursiveFunc)(id) // hide recursive typing behind dynamic typing
+
+Func fix(FuncFunc f)
+  Func r(RecursiveFunc g)
+    int s(int x)
+      return g(g)(x)
+    return f(s)
+  return r(r)
+
+int main(int argc, const char *argv[])
+  autoreleasepool
+
+    Func almost_fac(Func f)
+      return (int n | return n <= 1 ? 1 : n * f(n - 1))
+
+    Func almost_fib(Func f)
+      return (int n | return n <= 2 ? 1 : f(n - 1) + f(n - 2))
+
+    fib := fix(almost_fib)
+    fac := fix(almost_fac)
+
+    Log('fib(10) = %d', fib(10))
+    Log('fac(10) = %d', fac(10))
+
+  return 0