csl: Release OSS libraries

Finagle 6.31
Util 6.30
Scrooge 4.2
TwitterServer 1.16
Ostrich 9.14

RB_ID=774633
TBR=true

csl: bump lib versions

RB_ID=756082
TBR=true

Release CSL libraries (Sept 2015).

- Release finagle, ostrich, scrooge, twitter-server, util (Sept 2015).

RB_ID=747942

Release CSL stack

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Release CSL Stack

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release CSL OSS

release new minor version of all CSL OSS.

twitter-server: 1.11.0
scrooge: 3.19.0
finagle-*: 6.26.0
ostrich: 9.9.0
util: 6.25.0

RB_ID=701418
TBR=true

csl: Publish externally with pants, sbt, and friends

Problem

It's difficult to publish util, finagle, etc. because we haven't
updated them for the new maven-less world.

Solution

Scripts that make it easy to publish with sbt and pants.  Bumped
the server-set version because we stopped publishing thrift
externally in ci.  Changed an ExitGuard test which broke under
weird sbt conditions.

Result

We're in a position where we can start publishing finagle, etc
again!

RB_ID=633570

Bump all sbt projects (util, ostrich, finagle, twitter-server)

Problem

After looking at the finagle changelog, I discovered that we already had
entries for finagle 6.23.0 and more for the current version.
The previous version bump was then incorrect, the version needs to be
greater than 6.23.0.

Solution

Bump the minor version of finagle, and for consistency I did the same
thing for all the other related projects.
Close the current section of the finagle changelog and name it "6.24.0".

RB_ID=540180

finagle version 6.22.0

finagle version 6.20.0