Fstd2nc

* Support for ''scale_factor'' and ''offset'' attributes in metadata
files, as a rudimentary form of unit conversion.
* New --zlib option for compression of netCDF files.
* Some speed optimizations for converting to netCDF4:
- Chunk size is set equal to FSTD record size.
- FSTD records are read in order, to better utilize buffering /
read-ahead on the input file(s).

* ''station_id'' axis for series files.
* Allow --squash-forecasts to work on series data (only with one date
of origin).
* New --subgrid-axis option for splitting supergrids (e.g. yinyang)
into multiple sub-grids that are aligned on a ''subgrid'' axis.
* Experimental [https://github.com/pydap/pydap pydap] plugin for
browsing FSTD files through a web interface. To test it:
python -m pydap.wsgi.app
* Allow directory names and wildcard patterns (surrounded by quotes)
as inputs to the converter.
* Speed optimizations for RPN date and IP1 value conversions.
* Speed optimizations for data type detection (dtype_fst2numpy).
* Speed optimizations for --filter option
* Experimental (and undocumented) --quick-scan option to quickly
extract record headers from input files. Gives a good speed boost
when reading many input files, but relies on some internal structures
of librmn.
* New --msglvl option to control verbosity of librmn messages.
Default is changed to display only warning / error. Old behaviour
can be restored by using --msglvl=INFORM.

* Make ''time'' dimension unlimited in the netCDF file.
* New --nc-format parameter to control the type of netCDF file being
created.
* Verify input file(s) are RPN files before trying to convert them.
* New --force option to overwrite the netCDF file if it already exists.
* New --filter option to select records based on some criteria
(e.g. "--filter ip1==24" to select 24-hour forecasts only).
* Some decoding of vertical coordinate for series data.
* Make sure nomvars are valid netCDF variable names, otherwise prepend
an underscore to them so the netCDF library doesn't complain.
* Remove degenerate ni/nj axes from the output file, and remove
degenerate time axes which contain dummy RPN dates.
* Support for 'U' grids ("supergrids").

* Bug fix for station name decoding (series files).
* New --metadata-file option for adding arbitrary metadata to the
netCDF file.
* Wrap all messages with gettext, to facilitate translation to French.
Note: no actual translations done yet.
* New --minimal-metadata option to strip out FSTD-specific metadata
from the netCDF file (such as kind, datyp, npas, etc.).
* Support for multiple input files.
* Write the command invocation into a global "history" attribute of
the netCDF file. Can be disabled by new option --no-history.
* When fudging variable names to make them unique in the output file,
use more context-specific modifiers such as etiket, typvar, etc.
instead of an integer counter.
* Warn when variable / dimension names have to be modified.
* New --ignore-typvar option to allow records with different typvars
to be combined into a single variable.
* New --reference-date option to control the reference date of the
time axis.

* Check if netCDF output file already exists, and prompt the user
before overwriting.
* Check if input file exists before trying to convert it.
* Some support for series files.
* Some more metadata for identifying horizontal and time dimensions.
* Some support for masked data. Detects records that have an '' in
their typvar, and looks for a corresponding mask record (typvar='').
* New --ignore-etiket option to allow records with different etikets
to be combined into a single output variable.