Fixed build.xml and made some clean up

Made some minor changes:
 * Fixed some problems in build.xml, now it works and can launch
 * Makefiles with the -j parameter thanks to the "tn" Ant option
 * Cleaned up some rubbish in obj/ subtree
 * Added the bin/ subtree

Signed-off-by: Raffaele Aquilone <aquiloneraf@gmail.com>