add typing hints to make it easier for 3rd party developers to use the library (#90)

* add typing hints to make it easier for 3rd party developers to use the library

* remove unused devicetype enum to support python3.3

* add python 3.3 to travis and tox, install typing module in setup.py

tox.ini

@@ -1,8 +1,9 @@
 [tox]
-envlist=py34,py35,py36,flake8
+envlist=py33,py34,py35,py36,flake8
 
 [tox:travis]
 2.7 = py27
+3.3 = py34
 3.4 = py34
 3.5 = py35
 3.6 = py36
@@ -13,6 +14,7 @@ deps=
   pytest
   pytest-cov
   voluptuous
+  typing
 commands=
     py.test --cov pyHS100
 
@@ -20,5 +22,9 @@ commands=
 deps=flake8
 commands=flake8 pyHS100
 
+[testenv:typing]
+deps=mypy
+commands=mypy --silent-imports pyHS100
+
 [flake8]
 exclude = .git,.tox,__pycache__,pyHS100/tests/fakes.py