pylint fixes

- exclude _version.py from linting
- add simle doc string to __init__.py because pylint wants it

.pylintrc

@@ -10,7 +10,7 @@
 
 # Add files or directories to the blacklist. They should be base names, not
 # paths.
-ignore=
+ignore=_version.py
 
 # Add files or directories matching the regex patterns to the blacklist. The
 # regex matches against base names, not paths.

pmda/__init__.py

@@ -7,6 +7,25 @@
 #
 # Released under the GNU Public Licence, v2 or any higher version
 
+"""
+PMDA --- Parallel MDAnalysis
+============================
+
+Ready to use analysis and buildings blocks to write parallel analysis
+algorithms using MDAnalysis with dask.
+
+The full documentation can be found at https://www.mdanalysis.org/pmda/.
+
+Note that by default no modules are imported in the top-level name
+space. Import what you need::
+
+   import pmda.parallel
+   import pmda.custom
+   import pmda.rms
+   import pmda.contacts
+
+"""
+
 from ._version import get_versions
 __version__ = get_versions()['version']
 del get_versions