Publish for Scala 2.11.0-M4

Published using `publish-signed`.

With pgp plugin loaded in ~/.sbt/plugins/plugins.sbt:

```
addSbtPlugin("com.typesafe.sbt" % "sbt-pgp" % "0.8")
```

Using sonatype with ~/.ivy2/.credentials:

```
realm=Sonatype Nexus Repository Manager
host=oss.sonatype.org
user=???
password=???
```

Upgraded SBT version to the latest 0.12,
as 0.12.1 had a bug that kept me from publishing.
Merge pull request #4 from adriaanm/publish-2.11.0-M4

Publish for Scala 2.11.0-M4
Removing build.sbt.
Moving to snapshot.
2.11.0-M5
SNAPSHOT
Document release process.

I was a little bit confused how actors migration should be published
to Maven Central so I decided to document it.
Merge pull request #5 from gkossakowski/document-releasing

Document release process.
Testing with 2.11.0-M6.
Back to snapshot.
Merge branch 'master' of https://github.com/scala/actors-migration
11.0.0-M7
2.11.0-M8
Modularize build, migrate to sbt 0.13.1
Travis CI
More fine-grained dependency to facilitate scala release automation.

Also bumping version to 1.1.0-SNAPSHOT