Add missing language.implicitConversions imports

cache/src/main/scala/coursier/Platform.scala

@@ -1,7 +1,8 @@
 package coursier
 
 import java.io._
-import java.net.URL
+
+import scala.language.implicitConversions
 
 import scalaz._
 import scalaz.concurrent.Task

core/shared/src/main/scala/coursier/ivy/Pattern.scala

@@ -1,5 +1,7 @@
 package coursier.ivy
 
+import scala.language.implicitConversions
+
 import scalaz._, Scalaz._
 
 import fastparse.all._

fetch-js/src/main/scala/coursier/Platform.scala

@@ -4,6 +4,8 @@ import org.scalajs.dom.raw.{ Event, XMLHttpRequest }
 
 import scala.concurrent.{ ExecutionContext, Promise, Future }
 
+import scala.language.implicitConversions
+
 import scala.scalajs.js
 import js.Dynamic.{ global => g }
 

plugin/src/main/scala-2.10/coursier/Structure.scala

@@ -2,6 +2,8 @@ package coursier
 
 import sbt._
 
+import scala.language.implicitConversions
+
 // things from sbt-structure
 object Structure {
   import Def.Initialize._