[ECommons-Models] Extracted ElementProxy interface

Signed-off-by: Stephan Wahlbrink <sw@wahlbrink.eu>
[ECommons-Collections] Added minor tweaks

Signed-off-by: Stephan Wahlbrink <sw@wahlbrink.eu>
[Lucene] Removed lucene plug-ins (moved to 3rdparty-lucene)

Signed-off-by: Stephan Wahlbrink <sw@wahlbrink.eu>