add Circle CI support

Created by: dulmandakh

this PR is trying to add Circle CI support. I found that RN and Fresco use Circle CI, but also many open source projects.

It builds BUCK in 4 minutes (https://circleci.com/gh/dulmandakh/buck/28), while Travis CI in 14 minutes (https://travis-ci.org/facebook/buck/jobs/453861250). But unit test is failed (https://circleci.com/gh/dulmandakh/buck/29).

OpenJDK 64-Bit Server VM warning: ignoring option UseSplitVerifier; support was removed in 8.0
FAIL    <100ms  0 Passed   0 Skipped   1 Failed   //test/com/facebook/buck/jvm/java/abi/source:source
FAILURE //test/com/facebook/buck/jvm/java/abi/source:source main: Command failed with exit code 137.
stderr: OpenJDK 64-Bit Server VM warning: ignoring option UseSplitVerifier; support was removed in 8.0

  When running <junit>.
com.facebook.buck.step.StepFailedException: Command failed with exit code 137.
stderr: OpenJDK 64-Bit Server VM warning: ignoring option UseSplitVerifier; support was removed in 8.0

  When running <junit>.
	at com.facebook.buck.step.StepFailedException.createForFailingStepWithException(StepFailedException.java:57)
	at com.facebook.buck.step.StepFailedException.createForFailingStepWithExitCode(StepFailedException.java:51)
	at com.facebook.buck.step.DefaultStepRunner.runStepForBuildTarget(DefaultStepRunner.java:54)
	at com.facebook.buck.cli.TestRunning.lambda$3(TestRunning.java:819)
	at com.facebook.buck.util.concurrent.WeightedListeningExecutorService.lambda$0(WeightedListeningExecutorService.java:74)
	at com.google.common.util.concurrent.AbstractTransformFuture$AsyncTransformFuture.doTransform(AbstractTransformFuture.java:206)
	at com.google.common.util.concurrent.AbstractTransformFuture$AsyncTransformFuture.doTransform(AbstractTransformFuture.java:195)
	at com.google.common.util.concurrent.AbstractTransformFuture.run(AbstractTransformFuture.java:115)
	at com.google.common.util.concurrent.MoreExecutors$5$1.run(MoreExecutors.java:999)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
Caused by: com.facebook.buck.core.exceptions.HumanReadableException: Command failed with exit code 137.
stderr: OpenJDK 64-Bit Server VM warning: ignoring option UseSplitVerifier; support was removed in 8.0

	at com.facebook.buck.step.StepFailedException.createForFailingStepWithExitCode(StepFailedException.java:52)
	... 10 more

I'll add NDK and other tests once above failure resolved. Please help.

Also I'm planning to add brew and Debian package build jobs, and utilize cache.