Python 3 support

[try2code]

Python 3 support

[a8dx]

I think that'd be fantastic - I'm working exclusively in 2.7, but could imagine eventually making the transition. CDO is pretty essential to my workflow, so then I'd be off and running. Thanks!

[Try2Code]

With last commit I took over the python3 changes. All test run successfully now with the default netcdf4 module. 'scipy' also works with python3, but crashes with python2.

@jhamman : Would be nice, if you could confirm this. thanks!

[jhamman]

I just update my libs so I can use GRIB. I'm still getting failing tests but they are not unique to the python3 branch nor are they unique to netCDF module used.

Here's the specs for my system:

PY2_version: Python 2.7.8 :: Anaconda 2.1.0 (x86_64)
PY3_version: Python 3.3.5 :: Anaconda 2.1.0 (x86_64)

netCDF4 module: 1.1.1 :: np19py27_0)
scipy module: 0.14.0 ::np19py27_0)   

CDO Version:
Climate Data Operators version 1.6.4 (http://code.zmaw.de/projects/cdo)
Compiled: by root on Joes-iMac.local (x86_64-apple-darwin13.4.0) Oct 15 2014 07:52:59
Compiler: /usr/bin/clang -pipe -Os -arch x86_64  -D_THREAD_SAFE -pthread
 version: unknown
Features: PTHREADS NC4 OPeNDAP Z JASPER UDUNITS2 PROJ.4 FFTW3
Libraries: proj/4.7
Filetypes: srv ext ieg grb grb2 nc nc2 nc4 nc4c 
     CDI library version : 1.6.4 of Oct 15 2014 07:52:57
 CGRIBEX library version : 1.6.4 of Jun 27 2014 14:00:04
GRIB_API library version : 1.12.1
  netCDF library version : 4.3.2 of Oct  5 2014 12:24:20 $
    HDF5 library version : 1.8.13
 SERVICE library version : 1.3.2 of Oct 15 2014 07:52:56
   EXTRA library version : 1.3.2 of Oct 15 2014 07:52:56
     IEG library version : 1.3.2 of Oct 15 2014 07:52:56
    FILE library version : 1.8.2 of Oct 15 2014 07:52:56

Here are the current failing tests. These tests fail on the master branch and the feature/python3 branch using both CDF_MOD_NETCDF4 and CDF_MOD_SCIPY:

• test_diff
• test_outputOperators
• test_output_set_to_none
• test_simple

@Try2Code, are you getting all the tests to pass on the master branch?

[Try2Code]

1.2.4 is released

[Try2Code]

and thanks again for your help!