Added SampleLibraryTag

public/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/core/SampleLibraryTag.scala

+package nl.lumc.sasc.biopet.core
+
+import nl.lumc.sasc.biopet.core.config.Configurable
+import org.broadinstitute.gatk.utils.commandline.Argument
+
+/**
+ * Created by pjvan_thof on 2/16/15.
+ */
+trait SampleLibraryTag extends Configurable {
+  @Argument(doc = "Sample ID", shortName = "sample", required = false)
+  var sampleId: Option[String] = root match {
+    case tag: SampleLibraryTag => tag.sampleId
+    case _                     => None
+  }
+
+  @Argument(doc = "Library ID", shortName = "library", required = false)
+  var libId: Option[String] = root match {
+    case tag: SampleLibraryTag => tag.libId
+    case _                     => None
+  }
+}