update to vert.x 2.1.2

[zhaopuming]

Now that vert.x has come to a stable 2.1.x version, please update the clojure plugin to that.

If you don't have time, I'll try to make a pull request later :-)

[tobias]

The module should work fine against 2.1.2, but I went ahead and updated the build to test against 2.1.2. Is that what you mean?

[zhaopuming]

I'd like to see the new version on vert.x module registery :-)

[tobias]

I've released version 1.0.3 of the module, and it should be available in maven central sometime tonight. Once it shows up there, I'll add it to the module registry. Thanks for nudging me to release!