Improve PyPI packaging (#71)

* Move files for better setup.py packaging

* Update setup.py and configs for src layout

* Run tests on setup.py build

In effect, this tests that the setup.py configuration is correct.

coverage combine and coverage:paths are added to keep the displayed
coverage paths as src/ssh_audit/*.py instead of
.tox/$envname/**/site-packages/ssh_audit/*.py

* Remove unnecessary encoding declarations

Python 3 defaults to UTF-8 encoding.
https://docs.python.org/3/reference/lexical_analysis.html#encoding-declarations

* Remove shebang from colorama type stubs

Shouldn't need to be an executable.
Related: git has this file tracked as chmod -x.

setup.cfg

@@ -0,0 +1,44 @@
+[metadata]
+name = ssh-audit
+version = attr: ssh_audit.ssh_audit.VERSION
+author = Joe Testa
+author_email = jtesta@positronsecurity.com
+description = An SSH server & client configuration security auditing tool
+long_description = file: README.md
+long_description_content_type = text/markdown
+license_file = LICENSE
+url = https://github.com/jtesta/ssh-audit
+project_urls =
+    Source Code = https://github.com/jtesta/ssh-audit
+    Bug Tracker = https://github.com/jtesta/ssh-audit/issues
+classifiers =
+    Development Status :: 5 - Production/Stable
+    Intended Audience :: Information Technology
+    Intended Audience :: System Administrators
+    License :: OSI Approved :: MIT License
+    Operating System :: OS Independent
+    Programming Language :: Python :: 3
+    Programming Language :: Python :: 3.5
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
+    Programming Language :: Python :: Implementation :: CPython
+    Programming Language :: Python :: Implementation :: PyPy
+    Topic :: Security
+    Topic :: Security :: Cryptography
+
+[options]
+packages = find:
+package_dir =
+     = src
+python_requires = >=3.5,<4
+
+[options.packages.find]
+where = src
+
+[options.package_data]
+ssh_audit = policies/*
+
+[options.entry_points]
+console_scripts =
+    ssh-audit = ssh_audit.ssh_audit:main