Use sbt-assembly to build a jar containing jansi

The maven build includes jansi into the built jar using the
maven-shade-plugin.

Fixes part of #1. However, `sbt publish` publishes the ordinary
jar, not the assembly jar built by `sbt assembly`. Still to do.

build.sbt

@@ -26,3 +26,19 @@ javacOptions in doc := Seq("-source", "1.5")
 scalaModuleOsgiSettings
 
 OsgiKeys.exportPackage := Seq(s"scala.tools.jline.*;version=${version.value}")
+
+// exclude some files, same patterns as in `pom.xml`
+assemblyMergeStrategy in assembly := {
+  case PathList("META-INF", "maven", _ @ _*) =>
+    MergeStrategy.discard
+
+  case PathList(ps @ _*) if ps.last endsWith ".txt" =>
+    MergeStrategy.discard
+
+  case PathList("org", "fusesource", "hawtjni", "runtime", p) if p.startsWith("Jni") || p.contains("Flag") || p.startsWith("T32") || p.startsWith("NativeStats") =>
+    MergeStrategy.discard
+
+  case x =>
+    val oldStrategy = (assemblyMergeStrategy in assembly).value
+    oldStrategy(x)
+}

project/plugins.sbt

@@ -1,3 +1,5 @@
 addSbtPlugin("org.scala-lang.modules" % "scala-module-plugin" % "1.0.3")
 
 addSbtPlugin("com.typesafe.sbt" % "sbt-git" % "0.8.4")
+
+addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.13.0")