I've updated the plugin to use the latest Pegdown. Pegdown 1.4.0 fixes a lot of smaller issues, and really works better. I updated the plugin version to 1.1.0 if that makes sense, since it's been sitting at 1.0.0.RC1 for a while.
I hadn't run the actual tests, and something appears to be wrong. I'm getting odd NoClassDefFound errors when running the plugin's tests, even though the plugin was working fine on my older Grails 1.3.7 app. I'm going to do some research, but I don't think it's functional yet, even with such a simple change.
OK, here's what I've figured out: The dependency exports needed to be compile, not runtime. I was able to get the taglib tests to complete. However, there's something screwy with the String method tests. Apparently, Grails is now resetting the metaClass of String between tests — only the first one will run correctly.
I should probably replace the String class tests with ones that test the service instead, but I don't have time to fix it right this minute.
@Phil DeJarnett I agree with the upgrade of the version number and the version of Pegdown that the plugin relies on.
As you're the primary contributor these days, I've given you direct write access to the grails-markdown repo. Feel free to merge the code in when you've got it passing tests and go ahead and release a new version. I haven't been doing that much grails work the past year on my current gig and I don't want to get in your way. You've proven that you can handle the responsibility :).