Merge ~xavpaice/layer-snap:setup into ~stub/layer-snap:master

[Xav Paice]

Add a setup.py to help testing infrastructure install dependencies

While not useful for general packaging of a Charm layer, a setup.py
file does allow the layer's branch to be referenced directly
in a requires.txt file using a syntax like:

-e git+https://git.launchpad.net/layer-snap#egg=charms.layer

[Xav Paice (xavpaice)]

A large number of the LMA charms currently include in the requirements.txt file a line:

-e git+https://git.launchpad.net/~jjo/layer-snap@cab2b604695f39a81abe47b22b8426e44e66df8f#egg=charms.layer

We would like to be using currently maintained code.

[Stuart Bishop (stub)]

Seems sane

review: Approve

[Stuart Bishop (stub)]

However, won't this approach fail badly if more than one layer is using the trick?

diff --git a/lib/charms/layer/__init__.py b/lib/charms/layer/__init__.py
 new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/lib/charms/layer/__init__.py
diff --git a/setup.py b/setup.py
 new file mode 100755
index 0000000..cda60d7
--- /dev/null
+++ b/setup.py
@@ -0,0 +1,27 @@
+#!/usr/bin/env python
+
+import os
+from setuptools import setup
+
+here = os.path.abspath(os.path.dirname(__file__))
+
+with open(os.path.join(here, 'README.md')) as f:
+    README = f.read()
+
+setup(name='layer_snap',
+      version='1.0.0',
+      description='layer_snap',
+      long_description=README,
+      license='Apache License 2.0',
+      classifiers=[
+          "Development Status :: 5 - Production/Stable",
+          "Intended Audience :: Developers",
+          "Programming Language :: Python :: 3",
+      ],
+      url='https://git.launchpad.net/layer-snap',
+      package_dir={'': 'lib'},
+      packages=['charms/layer'],
+      include_package_data=True,
+      zip_safe=False,
+      install_requires=['charmhelpers', 'charms.reactive']
+      )