Raise memory requirements for gmap_build

public/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/extensions/gmap/GmapBuild.scala

@@ -40,7 +40,7 @@ class GmapBuild(val root: Configurable) extends BiopetCommandLineFunction with R
   /** genome database */
   var db: String = _
 
-  override def defaultCoreMemory = 15.0
+  override def defaultCoreMemory = 25.0
 
   override def versionRegex = """.* version (.*)""".r
   override def versionCommand = executable