Fix compilation errors

[twilco]

I love this crate — thanks for making it!

I noticed that compilation is broken with the latest nightlies. This PR fixes these, and changes norun to no_run (this attribute name must've changed as well). I'm not 100% on the semantic correctness here, so if something different should be done let me know.

error[E0609]: no field `filter` on type `&mut TestOpts`
   --> src/runner.rs:258:34
    |
258 |     if opts.filter_exact && opts.filter.as_ref().map_or(false, |s| s == real_test_name) {
    |                                  ^^^^^^ help: a field with a similar name exists: `filters`

error[E0609]: no field `filter` on type `&mut TestOpts`
   --> src/runner.rs:260:14
    |
260 |         opts.filter = Some(format!("{}::", real_test_name));
    |              ^^^^^^ help: a field with a similar name exists: `filters`

[twilco]

Oops, just saw #30, which looks way more comprehensive. I'm going to close this one.