add conda recipes for distributions

here are the conda recipes for distributions.

since protobuf is a dependency, we also provide a recipe for both libprotobuf (the C++ library) and protobuf (the python runtime). the python runtime dep has been pushed mainstream and is therefore not included, but the C++ library is trickier since distributions builds with libc++ and its unclear what the proper binstar/conda conventions for handling this (see https://groups.google.com/a/continuum.io/forum/#!mydiscussions/anaconda/XL6ei0pCVfo for complete silence on this topic).

in theory, you should be able to:

    $ conda config --add channels distributions # for libprotobuf/protobuf deps
    $ cd conda
    $ conda build distributions
    $ binstar upload [...] # you need the binstar credentials to do this step

the process is manual for the time being. ideally we'd integrate this into whatever workflow you currently have set up for making pip releases.