Reorganize tests into unit and functional tests

This commit breaks up the tests into 2 subdirectories, unit and functional.
Functional tests use the network in some way and may require either a
queries file or a functional config. Unit tests do not have these
requirements. In addition the default tox job is changed to only run the
unit tests. The functional tests are give a separate tox job.

Change-Id: I4bdc7f1098bfb7fa16dd869b2e54b3154848c3e1

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 1.6
-envlist = py26,py27,py33,pypy,pep8
+envlist = py26,py27,py33,pypy,pep8,functional
 skipsdist = True
 
 [testenv]
@@ -13,7 +13,10 @@ setenv =
    LC_ALL=C
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-commands = python setup.py testr --slowest --testr-args='{posargs}'
+commands = python setup.py testr --slowest --testr-args='{posargs} tests.unit'
+
+[testenv:functional]
+commands = python setup.py testr --slowest --testr-args='{posargs} tests.functional'
 
 [testenv:pep8]
 commands = flake8