* Added etcd installation instructions ptr
(cannot run integ tests w/o it).
* Removed unnecessary mercurial instructions
(install works w/o mercurial).
* Moved pre-commit hook installation instructions from development
loop to git clone section (it's a one time setup).
* Ditto for "setting upstream remote to no_push".
* Gathered Go install/upgrade discussion to one section.
* Put build/test instructions between checkout and commit.
Formerly, build was up before fork (odd), and test was
tacked at end of doc.
* Brought text into sync with the Workflow fig:
* Assured 1:1 correspondence between numbered figure steps
and numbered section headers - had no numbers before.
* Used "$working_dir", "$user" and "myfeature" in text to
match figure.
Jeffrey Regan