New filter gabella implementation.

TYPO: in the documentation

NEW: empirical attenuation estimation due to wetting of the radome

Changed code to make the shape of 3-D volumes generated by classes in
wradlib.vpr to follow the convention (...,z,y,x) in order to make it consistent
with the current polar convention (...,sweep,azimuth,range).

Main results from today's sprinting session.
A few functions to calculate mean profiles and to do simple corrections.

ENH: Added new keyword argument "show" to vis.polar_plot2 in order to allow multiple subplots.

The default value of show is True. If show is not explicitely passed, the behaviour
of the funciton remains unchanged (i.e. the plot is immediately shown). If show...

FIX: referring to revision no. 315, the Fix haven't worked proper, so here is hopefully a well-oiled update

Removed PyTables as a dependency from setup.py and from gettingstarted.rst

FIX: Removed PyTables dependency in wradlib.io

PyTables was used to allow convenience import/export of data arrays to/from
hdf5 files. This was implemented via wradlib.io.to_hdf5 and wradlib.io.from_hdf5.
However, PyTables tends to conflict particularly with the netCDF4 module, probably...

FIX: Changed order in which netCDF4 and tables is imported.

The former order procuced errors for the latest Python(x,y) release.

Merged in kai_muehlbauer/wradlib_miub (pull request #8)

New plot module in wrl.vis

FIX: a few changes concerning mainly the handling of keyword arguments during
initialization and plotting.

DOC: fixed typos, corrected some directorypaths

DOC: a few more minor changes

DOC: moved class description of cg_plot from __init__ to class docstring, so
that numpydoc puts it into the right place.

FIX: fixed a few paths to data files and datasets to get the cg_plot_demos
working

FIX: fixed an import error

STY: Some trailing whitespace removals

FIX: checked and corrected indentation of wradlib.vis.py

Added Example for cg_plot