Merge pull request #462 from apoloval/bump-master

Bump project version to 0.3-SNAPSHOT
Update modules diagram
Remove dead code
Style fixes
Document how cakes are composed
Merge pull request #463 from sortega/architecture

Update docs and add a new one about the cakes
Move platform detection to common

And add some tests
Add a new base class for unit tests
Add utilities for PIDs

Add classes per platform as this is not portable code.
Add PidFile class
Fix broken build on IntelliJ IDEA

The module `io.gatling.highcharts`, for some unknown reason, fails to fetch
when SBT is refresh from IntelliJ IDEA but not from SBT console. This is due
to version 2.1.0-SNAPSHOT doesn't exist anymore after 2.1.0 was released.
Prevent application from running twice with a pidfile
Make coinffeine-headless guarantee the peer is shutdown
Merge pull request #464 from apoloval/buildbreak

Fix broken build on IntelliJ IDEA
Merge pull request #465 from sortega/issue/193_pidfile

Introduce a pidfile to avoid having multiple instances running