- moved check_node_builtins to build_utils
- added --no-shutdown option for vagrant builds
- fixed typo in JNI lib output name on win32 (missing lib prefix)
- refactored all existing platform configs to align with new build-env APIs
- added graceful handling / shutdown of build-envs if user cancels the build early
- added powershell scripts for build dependencies
- corrected usage of "smb" mounted folders for macos:vagrant target
- added win32:vagrant target

- register atexit events before cross-builds are started
- switched linux & android docker images to Ubuntu Xenial LTS (see eclipsesource#311)
- cleaned up and documented switch-to-winrm-plugin that is used in win32:vagrant builds

Features
------------------------
[Build-System]
- replaced default Android instrumentation test runner with Spoon test runner
  (allows to optionally run individual tests on emulator)
- added interactive CLI mode (see build.py, build_interactive.py)
- added "--interactive, -i" CLI parameter to start interactive build CLI
- added support for specifying "anti-build-steps" via the CLI
  (for example: "all ~nodejs ~test" runs all steps, except for "nodejs" and "test")
- added "--vendor, -v" CLI parameter that allows to build specialized linux vendor binaries, e.g. for alpine-linux
- added alpine-linux binary support
- added "inject_env" API that is directly callable on a build-step config
- added "--sys-image, -img" CLI parameter that can be used to override the used OS image for Docker / Vagrant builds
- refactored the original "--cross-compile, -x" parameter into two separate parameters "--docker, -dkr" and "--vagrant, -vgr"
  (this makes it possible to support both variants for all target platforms)
- added "--keep-native-libs, -knl" CLI parameter
  (can be useful for building bundles that should include multiple platform binaries)
- centralized some repeated constant literals & code from build-steps across multiple platforms
  (into build_utils.py, cmake_utils.py and shared_build_steps.py)
- added automatically set "file_abi" property on build-step configs
- added more variables for use with "inject_env" API
- added "adb logcat" process to Android Docker build
  (writes realtime output from Android emulator to ./docker/android/logcat.txt)
- moved all Node.js utility code to nodejs.py CLI script
- added experimental code to package Node.js pre-built binary packages
  (see nodejs.py)

[J2V8]
- updated LibraryLoader code to include Linux-Vendor specifier when looking for native libs
  (vendor-specific libs are preferred over vendor-agnostic ones)
- added PlatformDetector as a central place to get normalized string identifiers for OS,Arch,Vendor

Fixes & Changes
------------------------
[Build-System]
- reorganized some code of the build-system into more separate files
  (see build.py, build_constants.py, build_executor.py, cli.py)
- added missing "bool" type to immutable.py
- throw error in CMake scripts if Java-Home could not be found
- default Docker base-image for Linux & Android builds is now "debian:jessie"
- installation of JDK in install.jdk.sh now checks if a JDK is already installed
  (needed for alpine-linux build)
- refactored win32 Dockerfile
  (now uses the same PowerShell scripts as the Vagrant build instead of inline commands)

[J2V8]
- separated LibraryLoader and Platform-Detection code
  (see PlatformDetector.java)
- show native lib-name in IllegalStateException message when native lib could not be loaded
- AllTests.java is now called A_RunAheadTests and only includes the V8RuntimeNotLoadedTest
  (this is the only test that should be run before any other tests)
- extended and refactored LibraryLoaderTest / PlatformDetectorTest implementations
- added timeout for V8LockerTest
- added workaround for V8RuntimeNotLoadedTest (is currently not implemented to run on Android)

- added build-util that directly sets the required build variables into the pom.xml file without using environment variables
- reverted gradle sdk- & target-versions back from 19 to 10
- added alias-functions for the polyfill shell commands to shared_build_steps.py
- started documenting the build-system modules & functions
- fixed git EOL problems for shell/python scripts used by Docker builds

- fix install.alpine.packages.sh chmod +x
- refactor nodejs.py sub-commands (git-CLI style)
- add j2v8-cli convenience scripts with command aliases (for win32/linux/macos)
- do not run NodeJsTest when native lib was not compiled with node features included
- add check in CMake node js lib scripts if all njs lib files exist, exit with error if any is missing
- add node 7.9.0 patch file (works for linux, but not windows currently)
- j2v8jni build-step is now called j2v8cpp
- j2v8jni is a new build-step using javah to regenerate J2V8 JNI header files
- j2v8jni build-step is skipped if the required V8.class file does not yet exist
- implement basic unit-testing for build-system
- centralize maven build-steps logic and also just run maven pre-build actions once per build-process
  (e.g. copy native J2V8 libs to the Java directories)

- some more documentation for the build CLI (in BUILDING.md)
- j2v8junit build-step is now called j2v8test
- added CLI feature to pass custom parameters to build-tools used in build-steps
- can now pass Maven/Gradle arguments to "--j2v8test" build-step
- reworked NodeJSTest skipping to also work for Android tests (spoon)
- fixed & improved shared java build-steps code

- small fix to Exception message for when the native lib can not be loaded
  (should show generic libname and vendor specific libname)

- we must use atexit to stop Vagrant VMs / Docker containers in case of an error

- improve merging of pre-defined and user build-params for `build -i`