Stop pointing twitter/commons users at the "old python" docs

Reviewed at https://rbcommons.com/s/twitter/r/693/
make build_configuration test happy on OSX, not just linux

"Looks like we need to toss in a realpath somewhere in these tests" was true

Also a couple of missing deps reared their head when I ran this test on its own

Testing Done:
./pants goal test tests/python/pants_test/base:build_configuration

./build-support/bin/ci.sh # on my mac

Linux still happy
https://travis-ci.org/pantsbuild/pants/builds/30092011

Reviewed at https://rbcommons.com/s/twitter/r/694/
Updated junit-runner to 0.0.41 to be able to use guava version > 15 exclude guava from junit-runner in BUILD.tools explicitly to show where you   need to update the guava version in case you want to use 17 or higher

Testing Done:
I've been using this in our repo to test.

PANTS_DEV=1 ./pants goal test tests/java::

Reviewed at https://rbcommons.com/s/twitter/r/691/
Cleanups to recent patch to pants goal depmap

Incorporated feedback from Patrick after submission of https://rbcommons.com/s/twitter/r/661/

Remove is_delegate attribute from AbstractTarget
Remove stray debug print message in a test

Testing Done:
ci passed at https://travis-ci.org/pantsbuild/pants/builds/30079790

Also ran pants goal depmap by hand on a dependencies() target in our repo

Bugs closed: 359

Reviewed at https://rbcommons.com/s/twitter/r/692/
Update the release docs and unify the pants semver.

This centralizes the pants version editing to
src/python/pants/version.py and firms up a manual release
process that will be dogfooded after this commit.

Outstanding work includes automation of release testing
and a scheme for editing & publishing a CHANGELOG.

Testing Done:
Ran the release test command block and that works - tail lines included in the docs itself.
Also burned a test site, see: http://pantsbuild.github.io/jsirois/release.html

Bugs closed: 357

Reviewed at https://rbcommons.com/s/twitter/r/690/
doc: committing someone else's change: not always straightforward

'./rbt patch -c 123' doesn't always work, so don't suggest
it so prominently

Testing Done:
Trying out the steps on this very commit.

Reviewed at https://rbcommons.com/s/twitter/r/699
Resurrected pants goal idea.

This mostly involved updating outdated references, and making utility functions to mimick functionality refactored long ago.

Source and Javadoc jars are not mapped in, and I'm not quite sure how to get that working again. I'd appreciate any input on that matter.

The code in idea_gen and ide_gen isn't very clean, because it wasn't very clean in the first place. It would be good to go back at some point and tidy it up.

Idea gen is also much more efficient than it used to be, thanks to the round manager: it now avoids compiling or jarring anything, which saves tons of time. It would still be nice to include a flag to optionally disable codegen, but I'm not sure how (un)trivial that is at this juncture.