[Python] Add updated pyarrow.* public API listing in Sphinx docs

[asfimport]

like https://github.com/pandas-dev/pandas/blob/master/doc/source/api.rst

Reporter: Wes McKinney / @wesm
Assignee: Wes McKinney / @wesm

Related issues:

• Arrow 0.3 release (blocks)

_{Note: This issue was originally created as ARROW-797. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
PR: #535

[asfimport]

Uwe Korn / @xhochy:
Issue resolved by pull request 535
#535