Added Ex. 2, polished script, added LICENSE

02_std.zig

@@ -0,0 +1,21 @@
+//
+// Oops! This program is supposed to print a line like our Hello World
+// example. But we forgot how to import the Zig Standard Library.
+//
+// Hint 1: The @import() built-in function returns a value representing
+//         imported code. We need to give that value a name to use it.
+// Hint 2: We use the name "std" in the main function (see below).
+// Hint 3: Imports need to be named by declaring them as "const" values.
+// Hint 4: Take a look at how the previous exercise did this!
+//
+@import("std");
+
+pub fn main() void {
+    std.debug.print("Standard Library.\n", .{});
+}
+
+// Going deeper: imports must be declared as "constants" (with the 'const'
+// keyword rather than "variables" (with the 'var' keyword) is that they
+// can only be used at "compile time" rather than "run time". Zig evaluates
+// const values at compile time. Don't worry if none of this makes sense
+// yet! See also this answer: https://stackoverflow.com/a/62567550/695615