Moved JARs, added ignores, fixed JUnit--see full description.

web-inf/classes and web-inf/appengine-generated added to .gitignore
files.

In order to run JUnit with appengine mocks, JARs from the appengine sdk
must be added to the build path. The JARs must exist in your root SDK
directory, so I cannot export them. I did add a duplicate JAR to
web-inf/lib so the code compiles even if you do not set the build path.
You should have the JARs just add these to your build path:

${SDK_ROOT}/lib/impl/appengine-api.jar
${SDK_ROOT}/lib/impl/appengine-api-labs.jar
${SDK_ROOT}/lib/impl/appengine-api-stubs.jar
${SDK_ROOT}/lib/testing/appengine-testing.jar

where SDK_ROOT is the appengine-sdk inside your eclipse plugin folder. I
exported a user library to the repo root which may or may not make it
easier.