Can't use breeze even after I added dependencies to build.sbt - scala

Question

I was following this tutorial on installing breeze, but I can't get it to work.
My directory structure:
myproject/
build.sbt
project/
Build.scala # This is empty
src/
main/
scala/
hello.scala
test/
scala/
my_tests.scala
My build.sbtlooks like this (It is mostly copied from the tutorial):
name := "My project"
libraryDependencies += "org.scalactic" %% "scalactic" % "3.0.0"
libraryDependencies += "org.scalatest" %% "scalatest" % "3.0.0" % "test"
libraryDependencies ++= Seq(
// other dependencies here
"org.scalanlp" %% "breeze" % "0.12",
// native libraries are not included by default. add this if you want them (as of 0.7)
// native libraries greatly improve performance, but increase jar sizes.
// It also packages various blas implementations, which have licenses that may or may not
// be compatible with the Apache License. No GPL code, as best I know.
"org.scalanlp" %% "breeze-natives" % "0.12",
// the visualization library is distributed separately as well.
// It depends on LGPL code.
"org.scalanlp" %% "breeze-viz" % "0.12"
)
resolvers ++= Seq(
// other resolvers here
// if you want to use snapshot builds (currently 0.12-SNAPSHOT), use this.
"Sonatype Snapshots" at "https://oss.sonatype.org/content/repositories/snapshots/",
"Sonatype Releases" at "https://oss.sonatype.org/content/repositories/releases/"
)
// or 2.11.5
scalaVersion := "2.11.8"
And my hello.scala file looks like this:
package mypackage
import breeze.linalg._
object Hello {
def main(args: Array[String]): Unit = {
println("Hello World")
val x = Dense.Vector.zeros[Double](5)
println(x)
}
}
The error that I get looks like this:
not found: value Dense
[error] val x = Dense.Vector.zeros[Double](5)
[error] ^
^
I know that I adding unit test related libraries to libraryDependencies correctly, because my unit tests work after I add them. But what am I doing wrong when adding dependencies for breeze? What steps should I take to narrow down the problem?