Move runtime code in project examples over to runtime component

The ability to download and expand (install) jars is a common utility that should not be at the top of a tree bundled into Project Examples. It would be better served somewhere more common and accessible by other plugins.

Code that belongs in runtime component and not project examples are:
1) downloadruntimes extension point
2) ECF transport class
3) DownloadRuntime
4) DownloadRuntimes
5) DownloadRuntimeViewerDialog
6) AS and Seam runtimes listed in o.j.t.examples' plugin.xml file declaring various application servers and seam runtimes as 'downloadruntimes'.

Moving these extensions will require a cleaner class for managing loading of extensions, and one for preferences. A messages class will be needed for o.j.t.runtime.core, and that's about it.