no longer needed since NetCDFFile has been removed
remove deprecated NetCDFFile
fix import
no regridding
use rita data from AOML for lic example.
remove un-needed imports
add new Line Integral Convolution (LIC) example (requires vectorplot scikit)
LogNorm: speed-up by dealing with mask explicitly
bugfix: handle alpha correctly in colormapping with uint8
add missing nc file to MANIFEST