Add precommit hooks & tox env to enforce code structure, add azure pipelines

Instead of leveraging hound & travis, add an option for azure pipelines,
which may replace the former in the future.

This also streamlines the contributing guidelines by:
* Adding pre-commit hooks to run isort, black, flake8, mypy
* Adding lint environment to allow checks to be run `tox -e lint`

This also contains a major cleanup to the SmartStrip handling which was due.
After seeing #184 I thought I should push this in as it is for comments before the codebase diverges too much.

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist=py35,py36,py37,flake8
+envlist=py35,py36,py37,flake8,linting,typing
 skip_missing_interpreters = True
 
 [tox:travis]
@@ -20,16 +20,31 @@ commands=
     py.test --cov --cov-config=tox.ini pyHS100
 
 [testenv:flake8]
-deps=flake8
+deps=
+  flake8
+  flake8-docstrings
 commands=flake8 pyHS100
-max-line-length=88
 
 [testenv:typing]
+skip_install=true
 deps=mypy
-commands=mypy --silent-imports pyHS100
+commands=mypy --ignore-missing-imports pyHS100
 
 [flake8]
-exclude = .git,.tox,__pycache__,pyHS100/tests/fakes.py
+exclude = .git,.tox,__pycache__,pyHS100/tests/newfakes.py,pyHS100/tests/test_fixtures.py
+max-line-length = 88
+per-file-ignores =
+  pyHS100/tests/*.py:D100,D101,D102,D103,D104
+  setup.py:D100
+ignore = D105, D107, E203, E501, W503
+#ignore = E203, E266, E501, W503, F403, F401
+#max-complexity = 18
+#select = B,C,E,F,W,T4,B9
+
+[testenv:lint]
+deps = pre-commit
+skip_install = true
+commands = pre-commit run --all-files
 
 [coverage:run]
 source = pyHS100
@@ -43,3 +58,12 @@ exclude_lines =
   # ignore abstract methods
   raise NotImplementedError
   def __repr__
+
+[isort]
+multi_line_output=3
+include_trailing_comma=True
+force_grid_wrap=0
+use_parentheses=True
+line_length=88
+known_first_party=pyHS100
+known_third_party=click,deprecation,pytest,setuptools,voluptuous