Fixes Issue #202
Fixes Issue #202

- __path__ was being set to a string
- It's supposed to be a list of strings or None

For pycapnp pydoc isn't super useful at the module level as pydoc will
scan all the files in the directory and just list them.

Here's thread_capnp for example, notice how it doesn't show any
information on the .capnp files.

Help on package thread_capnp:

NAME
    thread_capnp

PACKAGE CONTENTS
    addressbook
    async_calculator_client
    async_calculator_server
    async_client
    async_reconnecting_ssl_client
    async_server
    async_ssl_client
    async_ssl_server
    calculator_client
    calculator_server
    thread_client
    thread_server

DATA
    Example = <capnp.lib.capnp._InterfaceModule object>
    schema = <capnp.lib.capnp._ParsedSchema object>

SymbiFlow/pycapnp,jparyani/pycapnp,jparyani/pycapnp,SymbiFlow/pycapnp,jparyani/pycapnp,jparyani/pycapnp,SymbiFlow/pycapnp,SymbiFlow/pycapnp