Add FAQ section

docs/FAQ.rst

+========================================
+Frequently Asked Questions (FAQs)
+========================================
+
+-   I get a runtime error with `Click` complaining about the encoding
+
+    .. code-block:: python
+
+        RuntimeError('Click will abort further execution because Python 3 was configured to use ASCII as encoding for ...sk_SK.UTF-8, sl_SI.UTF-8, sr_YU.UTF-8, sv_SE.UTF-8, tr_TR.UTF-8, uk_UA.UTF-8, zh_CN.UTF-8, zh_HK.UTF-8, zh_TW.UTF-8')
+
+    This can be solved by :
+
+    .. code-block:: bash
+
+        export LC_ALL=en_US.utf-8
+        export LANG=en_US.utf-8

tox.ini

 [tox]
-envlist = py27, py34, py35, py36, flake8
+envlist = py36, py37, flake8
 
 [travis]
 python =
+    3.7: py37
     3.6: py36
-    3.5: py35
-    3.4: py34
-    2.7: py27
 
 [testenv:flake8]
 basepython = python