Merge pull request #36 from ndeverge/sbt-0.12.2

Add sbt-0.12.2 support
add sbt-0.12.3 support
Merge pull request #40 from xuwei-k/sbt0.12.3

add sbt-0.12.3 support
Always vendor JDK
Merge pull request #41 from heroku/vendorjdk

Always vendor JDK
Skip logging
skip doc generation
remove erroneous version from Heroku plugin
Merge pull request #43 from heroku/no-doc-gen

No doc gen
add opt/sbt-0.12.4.boot.properties
Merge pull request #47 from heroku/sbt-0.12.4

add opt/sbt-0.12.4.boot.properties
Trim the build for Play! 2 applications

Drop the following from the slug
- ${BUILD_DIR}/project/boot
- ${BUILD_DIR}/.jdk
- ${BUILD_DIR}/target/scala-*
- ${BUILD_DIR}/target/streams
- ${BUILD_DIR}/target/resolution-cache

This reduced my slug size from 142MB to 39MB ...