Remove erroneous whitespace in README

[larsks]

The example import statements in the README were indented, which meant
that if you were to try and copy-and-paste them into an interactive Python
prompt it would fail:

>>>    import pe
...    import pe.app
...    import pe.connect
...    import pe.handler
...    import pe.monitor
...
  File "<python-input-0>", line 1
    import pe
IndentationError: unexpected indent

This commit removes the indentation.