Update to tapestry-testng

A new version of tapestry-testng has been upload. The version number (1.0.0-SNAPSHOT) has not changed, but there's some new features:

• Uses TestNG 5.1, the latest version
• Supports running tests in parallel

The previous versions of tapestry-testng uses a simple instance variable to store the EasyMock control. This is insufficient for TestNG, which creates a single instance of a test case class, and then will invoke test methods on it from multiple threads. This new vesion of the library stores the EasyMock control in a thread local variable.

However, I'm still not 100% certain this will work properly due to how TestNG operates ... it doesn't seem to invoke cleanup methods from the correct thread. See this forum posting. If TestNG is, in fact, broken, then we'll have to wait for a TestNG 5.2 that fixes the issue.