Add full test environment.

Add a tox environment that will install all of the optional
packages and which will run with system site packages enabled
so that we pick up those tests as well. This should allow us
to run expansive tests on jenkins that aren't normally required
locally, but which are possible.

Change-Id: Iabd61874061e24950d4d2082a2fba158b4601624

tox.ini

@@ -14,7 +14,6 @@ deps = -r{toxinidir}/tools/pip-requires
 commands = nosetests {posargs}
 
 [tox:jenkins]
-sitepackages = True
 downloadcache = ~/cache/pip
 
 [testenv:pep8]
@@ -26,3 +25,9 @@ setenv = NOSE_WITH_COVERAGE=1
 
 [testenv:venv]
 commands = {posargs}
+
+[testenv:full]
+sitepackages = True
+deps = -r{toxinidir}/tools/pip-requires
+       -r{toxinidir}/tools/test-requires
+       -r{toxinidir}/tools/test-options