A few fixes to specs to make them pass under JRuby/Windows

I talked to lsegal about this a little bit on IRC last night.  This pull request fixes some problems with the YARD specs that were affecting it on JRuby and Windows.

After applying the changes in this pull request, I was able to get all of the specs to pass with JRuby 1.7.9 in Windows 8 64-bit.  The changes are explained in the commit messages, but let me know if you want more information or want me to try something.

The output below shows how I ran the specs and what the output was:

```
$ bundle exec rake
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Pending:
  YARD::Templates::Helpers::HtmlHelper#htmlify should autolink URLs (markdown sp
ecific)
    # This test depends on a markdown engine that supports autolinking
    # ./spec/templates/helpers/html_helper_spec.rb:150

Finished in 15.59 seconds
1659 examples, 0 failures, 1 pending
```

I think that JRuby 1.7.9 must have a working implementation of Ripper, because the tests pass whether or not I supply the LEGACY environment variable.  Hooray!