ClojureVerticleFactory should serialize verticle start()

[tobias]

If clojure.jar is on the classpath, verticles don't get isolated runtimes, which isn't really a problem in itself, but does cause issues with namespaces being accessed before they are completely loaded. Serializing start() should prevent that.

[tobias]

I now realize this is also an issue even when you don't have a clojure.jar on the classpath, since multiple instances of the same verticle will share the same runtime, and may collide loading namespaces there as well.

[prio]

Hi Toby. Have been testing this since last Friday and my application is behaving much better, no longer seeing the errors I was previously seeing when restarting.

[tobias]

@prio - thanks for the feedback! This has been released in v1.0.5 if you want to move past the SNAPSHOT.