Fix incremental compilation when a Scala project depends on a Java project (#414)

* Upgrade ammonite to 1.1.2-30-53edc31

This is mainly to get https://github.com/lihaoyi/Ammonite/pull/851 which
should reduce the amount of unnecessary work done by incremental
compilation in the Mill build. This requires some code changes since
this means we now depend on a more recent version of coursier, as a
side-effect this means that we do not depend on scalaz anymore.

Also use the same ammonite version in the Mill build and in
ScalaModule#ammoniteReplClasspath.

Also remove an incorrect dependency in the caffeine integration test.
This was always wrong but did not start failing until this commit,
probably due to dependencies appearing in a different order on the
classpath.

* Rename ScalaWorker to ZincWorker

Starting with the next commit, it will be used in Java-only projects
too, so the name is misleading.

* Upgrade to Zinc 1.2.1

* Fix incremental compilation when a Scala project depends on a Java project

Before this commit, JavaModule#compile simply called javac
unconditionally, thus generating new classfiles every time. But if a
Scala project depends on a Java project, this will throw off the
incremental compilation algorithm which will unnecessarily recompile
files. To avoid this we now use Zinc to compile Java projects too (as a
bonus this means that Java compilation becomes incremental). This
required some refactoring in ZincWorkerImpl to be able to compile stuff
without having to pass Scala-specific options.

The issue solved by this commit could be reproduced by running in the
Mill repository:

$ mill main.compile
$ mill -i
@ main.compile()

and observing that before this commit, the `main.compile()` call ended
up recompiling code.

1 files changed, 3 insertions, 4 deletions

diff --git a/integration/test/resources/caffeine/build.sc b/integration/test/resources/caffeine/build.sc
index aaa66626..a4967f31 100644
--- a/integration/test/resources/caffeine/build.sc
+++ b/integration/test/resources/caffeine/build.sc
@@ -8,11 +8,11 @@ import deps.{benchmarkLibraries, benchmarkVersions, libraries, testLibraries, te
 
 trait CaffeineModule extends MavenModule{
   def repositories = super.repositories ++ Seq(
-    coursier.ivy.IvyRepository(
+    coursier.ivy.IvyRepository.parse(
       "https://dl.bintray.com/sbt/sbt-plugin-releases/" +
       coursier.ivy.Pattern.default.string,
       dropInfoAttributes = true
-    ),
+    ).toOption.get,
     MavenRepository("https://jcenter.bintray.com/"),
     MavenRepository("https://jitpack.io/"),
     MavenRepository("http://repo.spring.io/plugins-release")
@@ -25,7 +25,6 @@ trait CaffeineModule extends MavenModule{
       libraries.guava,
       testLibraries.mockito,
       testLibraries.hamcrest,
-      ivy"org.hamcrest:hamcrest-library:1.3",
       testLibraries.awaitility,
     ) ++
       testLibraries.testng ++
@@ -151,4 +150,4 @@ object simulator extends CaffeineModule {
 
     def ivyDeps = super.ivyDeps() ++ testLibraries.testng
   }
-}
\ No newline at end of file
+}