Automate builds with Eclipse Tycho

While Eclipse Tycho is unbelievably awful, it's still better than nothing. Apparently a good percentage (50%+) of Eclipse plug-ins are using it for their builds.

To invoke:

* All plug-ins may be built using `mvn compile`.
* All tests may be run using `mvn integration-test.`

Currently, there are failing tests and they are ignored so that Maven will continue to run the remaining tests. A number of these failures are probably due to the test harness. Once the test failures are fixed, we can disable ignoring test failures. After that, we can set up continuous integration with Travis CI.

Other alterations:

* Added a root `.project` file so root files like the parent pom were easier to edit in Eclipse.
* Added `target/` to root `.gitignore` since Maven uses `target/` subdirectories for builds.

As an added bonus, easymock is now obtained from Eclipse Orbit. This should mean that we can drop easymock from the repository.