Finalized changes to be able to export the plugin.

- removed the generated export Ant script: it's crappy since it has a static qualifier (I would have liked it to get the current date when exporting)
- updated/fixed versions of dependencies of the plugin
- added the `bin` folder to the OSGI classpath definition, so that the plugin can be exported and run as is
- added a rule to ignore the `export` folder at the root of the project: that's the folder in which we should export the plugin