Preventing Activity restarting on newer Android versions, updating build target and fixing .classpath

1. Fixed issues with .classpath entry orders and missing attributes.

2. Adjusted build targets, so there should be no problems with code from newer Android API versions.

3. Added "screenSize" to the list of configChanges in AndroidManifest.xml, thus preventing unnessecary activity restarts. See discussion at issue #42

Importing the project from git in eclipse (with current Android SDK and ADT plugin) as an "existing project" should now be enough to build it and run it without errors or further configuration. If this is not the case for you, please write a comment here.