DOC: Many docs improvements.

- Generate links to sourcecode via the Sphinx `viewcode` extension.
- Generate reference docs for Asset/Equity/Future, AssetFinder, and
  AssetDBWriter.
- Generate reference docs for Pipeline API classes.
- Fix broken links and formatting issues in the 0.8.4 whatsnew.
- Use embedsignature in _assets.pyx so that the signatures of Asset
  subclasses are inspectable.

docs/source/appendix.rst

@@ -1,8 +1,62 @@
-Zipline API
------------
+API Reference
+-------------
 
-For each of these api functions, the ``self`` argument is implicitly the current
-:class:`~zipline.algorithm.TradingAlgorithm`
+Algorithm API
+~~~~~~~~~~~~~
+
+The following methods are available for use in the ``initialize``,
+``handle_data`` and ``before_trading_start`` API functions.
+
+In all listed functions, the ``self`` argument is implicitly the
+currently-executing :class:`~zipline.algorithm.TradingAlgorithm` instance.
 
 .. automodule:: zipline.api
    :members:
+
+.. autoclass:: zipline.algorithm.TradingAlgorithm
+
+Pipeline API
+~~~~~~~~~~~~
+
+.. autoclass:: zipline.pipeline.Pipeline
+   :members:
+   :member-order: groupwise
+
+.. autoclass:: zipline.pipeline.CustomFactor
+   :members:
+   :member-order: groupwise
+
+.. autoclass:: zipline.pipeline.factors.Factor
+   :members: top, bottom, rank, percentile_between, isnan, notnan, isfinite,
+             eq, __add__, __sub__, __mul__, __div__, __mod__, __pow__, __lt__,
+             __le__, __ne__, __ge__, __gt__
+   :exclude-members: dtype
+   :member-order: bysource
+
+.. autoclass:: zipline.pipeline.filters.Filter
+   :members: __and__, __or__
+   :exclude-members: dtype
+
+Asset Metadata
+~~~~~~~~~~~~~~
+
+.. autoclass:: zipline.assets.assets.Asset
+   :members:
+
+.. autoclass:: zipline.assets.assets.Equity
+   :members:
+
+.. autoclass:: zipline.assets.assets.Future
+   :members:
+
+.. autoclass:: zipline.assets.assets.AssetFinder
+   :members:
+
+.. autoclass:: zipline.assets.assets.AssetFinderCachedEquities
+   :members:
+
+.. autoclass:: zipline.assets.asset_writer.AssetDBWriter
+   :members:
+
+.. autoclass:: zipline.assets.assets.AssetConvertible
+   :members: