Add documentation of __version__ variable in cobs and cobsr modules.

Author: cmcqueen

doc/source/cobs.cobs.rst

@@ -62,6 +62,14 @@ The function decodes a byte string according to the COBS method.
     input, and ``cobs.cobs.DecodeError`` is raised.
 
 
+``__version__`` -- package version information
+----------------------------------------------
+
+..  data:: __version__
+
+    The variable contains the package version number as a string.
+
+
 ..  _cobs-examples:
 
 Examples

doc/source/cobs.cobsr.rst

@@ -59,6 +59,14 @@ The function decodes a byte string according to the COBS/R method.
     ``cobs.cobsr.DecodeError`` exception will be raised.
 
 
+``__version__`` -- package version information
+----------------------------------------------
+
+..  data:: __version__
+
+    The variable contains the package version number as a string.
+
+
 ..  _cobsr-examples:
 
 Examples