Make __version__ a module-level attribute

By moving __version__ to __init__.py, it becomes an attribute of the
module.  This is recommended in PEP 396 and a common practice in many
contemporary packages.

This enables the following:

>>> import mypackage
>>> print(mypackage.__version__)
'5.2.0'

mypackage/__init__.py

@@ -1 +1,5 @@
+
+from .__version__ import VERSION
+__version__ = '.'.join(map(str, VERSION))
+
 from .core import *

mypackage/__version__.py

@@ -4,5 +4,3 @@
 # 88 YY 88  dP    88     dP""""Yb  YboodP 88  Yb dP""""Yb  YboodP 888888
 
 VERSION = (5, 2, 0)
-
-__version__ = '.'.join(map(str, VERSION))

setup.py

@@ -50,6 +50,7 @@ about = {}
 if not VERSION:
     with open(os.path.join(here, NAME, '__version__.py')) as f:
         exec(f.read(), about)
+        about['__version__'] = '.'.join(map(str, about['VERSION']))
 else:
     about['__version__'] = VERSION