Change [1] requires pip >= 7.0.1. In general, test
environments will need to have pip and virtualenv in line
with global requirements. Add a reference to the global
requirements rather than specifying versions that will
inevitably become stale.
Also adds inline literal markup to all occurences of "tox"
for consistency.
[1] Related-Change: I7c60be623b4340ee34ae1aa520f17b303348811d
Change-Id: I7730f22c594a3521973cb9ff264a7d50f2b86a1a
Depends-On: I45eee626713438af5fc676f2b5f636d7ec23f7be
fc24a2322d