Fix names in docstrings and DeprecationWarnings.

Update a number of docstrings and DeprecationWarnings to refer to
the correct methods or attributes.
Merge pull request #411 from jorgenschaefer/fix-deprecation-docstring-typo

Fix deprecation docstring typo
Always cast pr to er in _follow_statements_imports
Merge pull request #422 from fbergroth/fix-completion-params

Fix completion params
detect buildout and add buildout eggs to sys.path