[split] FuturePool.defaultPool: use cached threadpool by default.

The current behavior is dangerous: we use pools precisely *because* we
need to block. We’re using threads for concurrency here, not to
multiplex IO. So a fixed pool makes basically no sense (for a general
purpose case). A user could easily encounter bad resource exhaustion.

RB_ID=87936
[split] Fix Spool.foreachElem crashing on resoved spool with error

`Spool.foreachElem(...) ` crashes when called on resolved spool with
an error. This is caused by `next()` evaluation without checking for
`next.isReturn == true`.

Github-pull-request: https://github.com/twitter/util/pull/39
Signed-off-by: marius a. eriksen <marius@twitter.com>

RB_ID=89414
[split] {ostrich,util}/sbt: robust MD5 checking.

This helps with building on linux.

RB_ID=89350
[split] upgrading slf4j dependent projects All projects depending on slf4j-**** -> 1.6.1.

It was originally just ones that use slf4j-api/simple and maven-finagle-thrift-plugin, but with provided scopes and including slf4j-nop/jdk14, it's pretty much every project in the birdcage that has a slf4j dependency

RB_ID=88029
[split] util-logging: for file handlers, default to append=true since that was the default with FileHandlerConfig and is safer behavior

RB_ID=90475
[split] util-logging: fix ThrottledHandler to not leak memory

RB_ID=91036
[split] AsyncSemaphore: Use volatile vars for the active number and the waiters

RB_ID=91307
[split] release 5.3.13 of util + bump util to 5.3.14-SNAPSHOT

RB_ID=91874
TBR=true
[split] Comment out FileHandlerSpec SIGHUP test

RB_ID=94713
[split] util broken window patrol: fix up warnings

RB_ID=95035
[split] Future.join: support up to 22-tupled futures

RB_ID=95187
[split] com.twitter.concurrent.Serialized: make documentation more explicit

RB_ID=96691
[split] Update ScribeHandler to support concurrent enqueue while flush; send multiple batches if queued records are larger than transcationSize; and add a few stats.

RB_ID=96870
[split] util 5.3.14

RB_ID=98630
TBR=true
[split] core libraries v6

This comprises the following API breaking changes:

Util: A new, lean Promise implementation, with modified interrupt
semantics (RB_ID=94965); Duration and Time with true sentinels. Remove
dangerous implicit conversions (RB_ID=85968); Promise and Try
combinators don't catch fatal exceptions (RB_ID=91443)

Finagle: New client/server APIs and accompanying plumbing. These are
not yet exposed publicly. (RB_ID=81439 RB_ID=85541 RB_ID=90058)

RB_ID=98612
[split] util 6, ostrich 9, finagle 6

Util 6.0.0  2012-11-26

  * Removed future cancellation, which is now replaced with one-shot
  interrupts. These also carry a ``cause'' which will be used
  profitably in finagle.
  * A new, leaner Promise implemetnation
  * New implementations for Time and Duration with true sentinels
  * Promise, Try combinators no longer attempt to catch fatal
  exceptions

Finagle 6.0.0  2012/11/26

  * util 6.0.0 dependency
  * finagle-core: new client/server APIs; not yet exposed to users

RB_ID=99091
TBR=true
[split] util/finagle: use java.util.ArrayDeque in place of mutable.Queue

Due to a space leak: https://issues.scala-lang.org/browse/SI-6690

RB_ID=98698
[split] util/finagle 6.0.1

  * Use java.util.ArrayDeque in place of mutable.Queue due to
  https://issues.scala-lang.org/browse/SI-6690

RB_ID=99116
TBR=true
[split] util-core: small modifications for thinner Promises - remove Future tracing - add the Transforming state referenced in the implementation it avoid creating chains of interrupt-forwarding PartialFunctions

RB_ID=100771
[split] zookeeper-client version coordination in accordance with AWESEOME-1257

RB_ID=101607