CDO

New features:

• Using libtool for linking (rpath)
• Changed predefined gaussian grid names from t<RES>grid to n<N>
  Use n80 instead of t106grid to define a Gaussian N80 grid
• Changed percentile parameter type from integer to float

New operators:

• bandpass: Bandpass filtering
• lowpass: Lowpass filtering
• highpass: Highpass filtering

Changed operators:

• eca_gsl: adjust implementation to fit definition by ECA
• expr, exprf: added missing values support

Fixed bugs:

• sellevel: copy zaxis meta data name and units
• seldate: open output file only when time steps found