REVIEW-4369: spec updates (mostly open issues)
update version on master to 2.0
reset release notes on master
Updates to story reflecting reality, not assumptions

I had previously assumed that ivy source/javadoc artifacts could be downloaded if they followed the maven naming convention. Turns out this was wrong. This means there's no backward compatibility to deal with :).
Gradle 3.0 is next major release.
Added some notes to various stories.
temporally fix failing integration tests for deprecations (TODO convert warnings to errors as claimed in our deprecation messages)
Merge branch 'release'
Java incremental compilation. Made the input jar change processing working more closely to what we want. The commit is pretty meaty, but 99% changes apply to new 'incremental' classes, which are somewhat volatile for the time being.
Merge remote-tracking branch 'origin/release'
Garbage collected some completed stories.
Moved story earlier in spec.
Driven by user questions, added a bit more docs and a sample to the test logging container.
Improved the TestNG listeners a little bit. Now any custom TestNG listeners are applied before Gradle's listeners. This way, the custom listener is more robust and can change test status. There might be some impact of this change hence mentioned in the notes.
Add initial support for configuring platform toolchain via dsl.
some cleanup in GccToolChain for configuring platform specific tools; remove old TargetPlatformConfiguration support
improve ivy test fixtures

- handle ext attribute
- provide access to any ivy artifact
rename/move maven-specific artifact resolution test
add ivy-specific artifact resolution test
factor out maven candidate artifact computation into separate class