[TOREE-431] Explicit add Guava dependency to kernel module

Fix the Toree build when depending on Spark 2.2.0 by forcing
the guava dependency to kernel module.

Closes #131
diff --git a/kernel/build.sbt b/kernel/build.sbt
index 5428b6e..99951cd 100644
--- a/kernel/build.sbt
+++ b/kernel/build.sbt
@@ -16,9 +16,9 @@
  */
 fork in Test := true
 libraryDependencies ++= Dependencies.sparkAll.value
+libraryDependencies += Dependencies.guava
 
 //
 // TEST DEPENDENCIES
 //
 libraryDependencies += Dependencies.akkaTestkit % "test"
-
diff --git a/project/Dependencies.scala b/project/Dependencies.scala
index 462648a..f8db4db 100644
--- a/project/Dependencies.scala
+++ b/project/Dependencies.scala
@@ -67,6 +67,8 @@
 
   val springCore = "org.springframework" % "spring-core" % "4.1.1.RELEASE"// Apache v2
 
+  val guava = "com.google.guava" % "guava" % "14.0.1" // Apache v2
+
   // Projects
 
   val sparkAll = Def.setting{