change some netcdf4 stuff in travis. also make delay import reraise the import error. trying to track down #150
another try
force netcdf4==1.0.4
add comment to .travis.yml to explain why we're requiring a specific version of netcdf4
Merge pull request #151 from rmcgibbo/travis

change some netcdf4 stuff in travis. also make delay import reraise the ...