twitter-server: Fix library name inconsistency and fmt in README/docsite

The naming used in TwitterServer's doc site is all over the place. In
different places, the library is called TwitterServer, Twitter-server,
and twitter-server. This change standardizes on "TwitterServer" as the
logical library name and "twitter-server" for the artifact name. Doc
source files are fmt'd, too.

RB_ID=536791
Update sbt projet definitions of (util, ostrich, scoorge, twitter-server)

Problem

In order to release our libraries for the open-source community, we need to update
the version of those.

Solution

Update the version in the sbt project definition.
While I was there, update also sbt to the latest version and increase the jvm
configuration for the code cache.

RB_ID=537603