Jongleur1983/osm2world

close streams that have been kept open (fixing possible memory leaks)
replacing deprecated GLPbuffer class by GLOffscreenAutoDrawable for Image-Export
fix a NullReferenceException on Menu Action when no camera is defined (e.g. before loading data)
use some generics in  FileDrop.java

addding a few generated SerialVersionUIDs to make the code checker happy ("fixes" warnings in eclipse)
removed a few imports