Support for writing layers to multi-layer files.

TODO: documentation (docstrings and manual)
Add new tests to get to 100% Python coverage in fiona.

Coverage isn't measured for Cython code.
Update readme and change log for 0.16
Add listlayers, open, prop_width to __init__py:__all__

This surfaces the function docs in help(fiona).
Add API docs

API doc sources are generated by "make apidocs". The modules.rst
file is then pulled into index.rst.
Reset reading of layers whenever we create a new iterator.
Test of iterator and layer reset.
Updates changes.
Update for 0.16.1.
Add prop_type function (#51).

Also a change to the mapping in ogrext.pyx so this works on
Python 2.6/7 as well as 3+.
README improvements.
Removed this_bis.py

I don't think anything in there added to the Zen of Python.
More README improvements.
Move data and time classes to fiona.rfc3339 module.
Permit use of UTF-8 encoded paths on Python 2 (#51).

For Python 3+, paths must always be str, never bytes.
Remove encoding from collection.meta.

This should be a layer creation (mode 'r') option only. OGR
provides no function to get the encoding of a layer and so there's
no straightforward way to copy it.
Support linking GDAL frameworks.

In the case that "gdal-config --libs" returns "-framework GDAL" we
put these in extra_link_args.
Introduction to multilayer data.
Ensure that a collection's name is always a string.

Complete the multilayer and VFS sections of the manual.
Update credits.

Including everyone in https://github.com/Toblerity/Fiona/contributors.