netCDF IO suport
I'd like to propose `read_netcdf` ([netCDF (Network Common Data Format)](http://www.unidata.ucar.edu/software/netcdf/)) a new Pandas I/O api feature with a similar top level interface as the other reader functions.  This format is widely used in the scientific community.   Furthermore, netCDF4 is implemented on top of the HDF5 library, making this a natural extension to functionality already in the api.  

Most likely this would sit on top of the exiting [Python/numpy interface to netCDF](https://code.google.com/p/netcdf4-python/), and because each variables metadata is stored in the file header, no complicated parsing would necessary. Multidimensional variables could be handled in a similar manner as hdf.

This may have been brought up in the past but my search here and on the google didn't bring anything up.
