Fix missing search&replace of .buildfile -> .build_file

Find cases of .buildfile and replace with .build_file.  Running python tests with coverage was broken.

Testing Done:
Ran python tests with PANTS_PY_COVERAGE=1

Reviewed at https://rbcommons.com/s/twitter/r/593/
rm java/examples/pingpong and many of its 3rdparty deps

rm {src|tests}/java/com/pants/examples/pingpong

rm -r 3rdparty/jvm/com/

3rdparty/BUILD -= ['guice', 'easymock']

3rdparty/BUILD -= ['mockito'] <- pingpong didn't use this; 'git grep' says nothing else did either

Testing Done:
https://travis-ci.org/pantsbuild/pants/builds/28428093

Reviewed at https://rbcommons.com/s/twitter/r/596/
Payloads with sources now give more useful errors for nesting

Because the creation of the Payloads happens later in the process
(rather than during the build file parsing), we still seem to lose track
of which file the error occurred in... is there a solution for that?

- Adds validation to SourcesMixin and switches it to inheritance with
  SourcesPayload
- Adds a Payloads test file

Reviewed on https://rbcommons.com/s/twitter/r/586/
doc: kick jar_library out of the list of Python-related BUILD file things

back when this was "dependencies", it made sense to list it with Pythonic things. Now, not so much.

Reviewed at https://rbcommons.com/s/twitter/r/598/
dev docs: talk about Travis-CI in one place, not two. Pull requests trigger CI

Mateo was surprised to find out a pull request gets Travis-CI's attention. I'd like to tease him for that, but, uhm, I didn't know it either. So document it. Once it's documented, I can tease the *next* nerd to hit this.

While I was in there, saw an old claim that pants_tests:all ran all the tests. But now our integration tests are separate. So tweaked that wording.

We had two places that talked about running all the tests (ci.sh/Travis). I was too lazy to add this pull-request blurb to both of 'em, so I consolidated. Now one of them is a hyperlink to the other.

Bugs closed: 267

Reviewed at https://rbcommons.com/s/twitter/r/597/
Add support for explicit absolute target address sepcs.

This provides a clear  way to refer to root level targets
from deeper in the BUILD tree.

Testing Done:
$ PANTS_DEV=1 ./pants goal test tests::

travis-ci went green here: https://travis-ci.org/pantsbuild/pants/builds/28347405

Bugs closed: 269, 272, 278

Reviewed at https://rbcommons.com/s/twitter/r/590/
Fixup ScalaLibrary dep injection - do this at BuildGraph population time.

This is effectively a restoration of 24681429b by Ryan Williams.

Previously ScalaLibrary runtime deps were injected in the classpath by
ScalaCompile at execute time.  This let downstream goals like test and
run that just use an aggregate classpath work, but it failed for any goal
needing correct deps at a per-target level like binary, bundle and publish.

This change introduces a scala TargetPlatform class as a very rough start
to centralizing the scala version to target and uses this in ScalaLibrary and
ZincUtils.

Testing Done:

Before:
=======
$ PANTS_DEV=1 ./pants goal bundle src/scala/com/pants/example/hello/exe
$ java -jar dist/exe-bundle/exe.jar
Exception in thread "main" java.lang.NoClassDefFoundError: scala/ScalaObject
...
$ tree dist/exe-bundle/
dist/exe-bundle/
├── exe.jar
└── libs

1 directory, 1 file

After:
======
$ PANTS_DEV=1 ./pants goal bundle src/scala/com/pants/example/hello/exe
$ java -jar dist/exe-bundle/exe.jar
$ java -jar dist/exe-bundle/exe.jar
Num args passed: 0. Stand by for welcome...
Hello, Resource World!
$ tree dist/exe-bundle/
dist/exe-bundle/
├── exe.jar
└── libs
    └── org.scala-lang-scala-library-2.9.3.jar -> /home/jsirois/dev/3rdparty/jsirois-pantsbuild-pants/.pants.d/ivy/mapped-jars/src.scala.com.pants.example.hello.exe.exe/org.scala-lang/scala-library/default/org.scala-lang-scala-library-2.9.3.jar

1 directory, 2 files

Bugs closed: 208, 256

Reviewed at https://rbcommons.com/s/twitter/r/581/
Link the payload test into all.

Testing Done:
$ PANTS_DEV=1 ./pants goal test tests/python/pants_test/base:all
09:01:48 00:00   [test]
09:01:48 00:00     [pytest]
09:01:48 00:00       [run]
                     ============== test session starts ===============
                     platform linux3 -- Python 2.6.8 -- py-1.4.20 -- pytest-2.5.2
                     plugins: cov, timeout
                     collected 65 items

                     tests/python/pants_test/base/test_double_dag.py ....
                     tests/python/pants_test/base/test_abbreviate_target_ids.py ....
                     tests/python/pants_test/base/test_cmd_line_spec_parser.py .....
                     tests/python/pants_test/base/test_generator.py ....
                     tests/python/pants_test/base/test_build_invalidator.py .
                     tests/python/pants_test/base/test_payload.py ...
                     tests/python/pants_test/base/test_build_file_parser.py ............
                     tests/python/pants_test/base/test_run_info.py ..
                     tests/python/pants_test/base/test_address.py ........
                     tests/python/pants_test/base/test_hash_utils.py ..
                     tests/python/pants_test/base/test_build_root.py ......
                     tests/python/pants_test/base/test_revision.py ......
                     tests/python/pants_test/base/test_build_file.py ........

                     =========== 65 passed in 0.45 seconds ============

09:02:21 00:33     [junit]
09:02:21 00:33     [specs]
               SUCCESS

Also:
$ comm -3 <(grep -A17 "name = 'base'" tests/python/pants_test/base/BUILD | grep pants | cut -d: -f2 | cut -d\' -f1 | sort) <(./pants goal list tests/python/pants_test/base: | cut -d: -f2 | sort)
	all
	base
	context_utils

The all and base targets are aggregators and context_utils is a python_library so linkage in base is now full.

Bugs closed: 285

Reviewed at https://rbcommons.com/s/twitter/r/602/
Add missed __init__.py
Kill support for legacy scrooge.

This change punts on cleaning up the ScroogeGen task
which now can be simplified a good deal.  The intent is
just to remove the possibility of folks binding to this capability
going forward.