cleanup & comment fix in finagle-mux

Problem

There was 1) inaccuracy in package doc for mux, 2) code duplicate, and 3) inconsistency in stat format

Solution

1) Correct the doc (finagle/finagle-mux/src/main/scala/com/twitter/finagle/mux/package.scala)
2) Remove the duplicate by calling a proper function
3) Make it consistent with the other stats

Result

discountWin is now logged as "21923064.bytes" rather than "21923064" (no other change in behavior.)
now the doc is consistent with the code, and the code looks a little better.

RB_ID=476213
Add stats to failure accrual

Problem

We do not record stats on FailureAccrual removals (and revivals)

Solution

Modify failure accrual to take a statsReceiver and use that to log
stats.  This highlights the problem that FailureAccrual is essentially a
factory Transformer that can do whatever it wants, so I additionally
deprecated that part of the API because I feel that it's too
open-ended (and certainly impossible to add stats to).  Instead, users
are encouraged to just supply failure accrual params and let us take
care of the transforming.

RB_ID=487093
util, finagle: add missing @RunWith annotation

Problem

The junit test runner for scala needs classes to have
the `@RunWith(classOf[JUnitRunner])` annotation attached
to classes in order to run them.

Solution

Add the annotation.

RB_ID=495921
finagle-core: add weights to NameTree.Union

Problem:

Weighted unions of names cannot be expressed in NameTrees.

Solution:

Change Union to contain (Double, NameTree[T]) pairs, fix parser and code
which walks NameTrees.

Result:

Weighted unions can be expressed in NameTrees.

RB_ID=494141
finagle-http: remove content length headers when chunking

Problem

Content-Length headers are not removed by Netty's compressors. This
causes content which is streamed, chunked, compressed, and also has a
Content-Length header to respond with the wrong value.

Solution

Always remove content length headers when streaming replies.

Discussion

This is a bad violation of modularity. Arguably the issue lies in
Netty here, and we should follow up.

RB_ID=496263
=Merge branch 'master' into sq_reserved/498209_util-6.22.2_1029222833

RB_ID=498209
TBR=true
NO-QUEUE=true
finagle: removed usage of java 7 api

Problem

finagle doesn't use java 7 features yet, but an
InetSocketAddress#getHostString snuck in.

Solution

Switch from InetSocketAddress#getHostString to
InetSocketAddress#getHostName, which may entail a DNS lookup

RB_ID=498061
=bump ostrich_2.10 to 9.6.4-SNAPSHOT

RB_ID=499001
TBR=true
NO-QUEUE=true