* largest-series-product: add to track

* Add note to largest-series-product tests about JUnit Rules

* remove Guava and use JUnit assert

* reassign old to Collection.unmodifiable

* reassign variable expected

Fix minor typo

Remove duplicate "the"

Standardize on JUnit 4.12

difference-of-squares: add to track

Journey builds trackler

Fix spacing around punctuation.
Expand out acronyms first and add contraction in parens.
Adjust list of built-ins.

Replace JodaTime in Meetup with standard lib

Remove duplicated lines

Track data has been factored into a separate gem: trackler.  The build
was breaking.
  (see also exercism/x-api#141)

Nice work! @jtigger

- ensure titles of tests match those in
  https://github.com/exercism/x-common/blob/master/exercises/pangram/canonical-data.json

Update ABOUT.md

Add quick start guide

Ignore all but first test in hello-world

- in journey test, remove @Ignores so that test runs exercise all tests.
- increase the verbosity of test logging to aide in seeing progress as
  tests are un@Ignored and solved.
- saving scripts used to make changes to all exercises.  These are the
  start of a library of scripts making such changes easier.
- make Gradle output more CI-friendly.

- in base build script, filter out @Ignores so that maintainers can run
  the full test suites.
- increase the verbosity of test logging to aide in seeing progress as
  tests are un@Ignored and solved.
- revamped GETTING_STARTED.md to reflect new output.  It is now a
  complete guide from start to finish with calls-to-action at the end of
  the instructions.

Initial POC of how to ignore all-but-first test

Describe how to get started with an exercise.

- Ensure only installation instructions are in INSTALLATION.md and only
  instructions for running tests are in TESTS.md.
- Remove install instructions for IDEs:
  - IDEs start to pay dividends when your codebase gets large enough that the refactoring and code navigation features start to seriously increase your efficiency; Exercism programs are, by design, toy-sized;
  - There are far fewer instructions to getting started when doing it from the command-line (and therefore less likely to get wrong).
- Focus on using package managers:
  - these tools provide the right kind of "magic" — you really don't need to know the installation details to start programming;
  - they automatically perform steps that can be hard to describe and do right (less likely to get wrong).

Add track icon.

Describe "simple" setup, leveraging the CI build.

Add there "exercises" key to config.json

- trimmed a bunch: the fewer words used, the more words read.
- removed step-by-step full setup in favor of referring to the CI
  script.

First step in transitioning from "problems" to "exercises".

Part of exercism/xjava#125.

Fixed typo "but the tests are expects"

A (partial) fix for the issue #2670

Use same version of Ruby X-API is: now 2.2.5.