Use sbteclipse 2.3.0 because 2.4.0+ has a bug that ignores unmanagedC…

…lasspath

sbt/sbt-eclipse#182

project/plugins.sbt

@@ -1,9 +1,5 @@
-// Most Scala projects are published to Sonatype, but Sonatype is not default
-// and it takes several hours to sync from Sonatype to Maven Central
-resolvers += "SonatypeReleases" at "http://oss.sonatype.org/content/repositories/releases/"
-
 // Run sbt eclipse to create Eclipse project file
-addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "2.5.0")
+addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "2.3.0")
 
 // Run sbt gen-idea to create IntelliJ project file
 addSbtPlugin("com.github.mpeltonen" % "sbt-idea" % "1.6.0")