use org.idryman.combinefiles to deal with large number of small files, significant speed up from 20 min to 2min
modified:   .settings/org.eclipse.jdt.core.prefs
new file:   lib/CombineFileDemo-0.0.1-SNAPSHOT.jar
modified:   mvn_install_lib.sh
modified:   pom.xml
new file:   src/main/java/org/voyiger/hadoop/basic/Softdrop2.java