Update libraries-and-tools.md

Added a new small c++ library
Documentation: remove "token" from discovery docs

It was a bit confusing how the term "token" was overriden in various ways in this doc. Clean it up by referring to it as a discovery URL.
Update clients-matrix.md
Documentation: fix timeout tuning TOML example

this makes the TOML example for tuning the peer election timeout
consistent with the guide's advice and with the other examples.
Typo fix
Merge pull request #918 from edwardcapriolo/patch-1

Update libraries-and-tools.md
Merge pull request #928 from grossws/patch-1

Typo fixes
Merge pull request #927 from bmatsuo/topic/Documentation/fix-tuning-timeout-toml

Documentation: fix timeout tuning TOML example
Merge pull request #1 from coreos/master

sync changes from author