use * for pointer type instead of &

See #770

To help automatically translate code, see the
zig-fmt-pointer-reform-2 branch.

This will convert all & into *. Due to the syntax
ambiguity (which is why we are making this change),
even address-of & will turn into *, so you'll have
to manually fix thes instances. You will be guaranteed
to get compile errors for them - expected 'type', found 'foo'

test/build_examples.zig

@@ -2,7 +2,7 @@ const tests = @import("tests.zig");
 const builtin = @import("builtin");
 const is_windows = builtin.os == builtin.Os.windows;
 
-pub fn addCases(cases: &tests.BuildExamplesContext) void {
+pub fn addCases(cases: *tests.BuildExamplesContext) void {
     cases.add("example/hello_world/hello.zig");
     cases.addC("example/hello_world/hello_libc.zig");
     cases.add("example/cat/main.zig");