Pv-atmos

Minor update, mainly bug fixes in mind. Changes concern CartWind2Sphere(), Make3D(), Sphere2xyz() and xyz2Sphere(). LoadData() now also check if file exists before trying to load it.

After v2.2 with more general coordinate reversal and logarithmic axes, pv_atmos.grids needed an update as well. The update is substantial, as a few input parameters have changed order. I apologize for the inconvenience as some of your code might have to be changed, but it seems worth it looking into the future. It also makes more sense for new users.

- logCoords and basis are now arrays to allow for multiple logarithmic
coordinates instead of only one.
- there are now additional inputs to LoadData (and thus also
TransformCoords): reverseCoords and revCenter. These are arrays that
tell pv_atmos which coordinates should be reversed (such as e.g.
pressure), and around which value
- The example files as well as the test_functions file now ask for the
path to pv_atmos instead of assuming something.
- Example and test files are modified to take into account the changes
to pv_atmos mentioned above

Main new functionality is LonLat2Pole() in pv_atmos.grids. This function allows to project longitude-latitude grids to be projected onto polar coordinates, either the South or the North pole.
In addition to this 2D operation, there is a 3D twist, in that the projection can be more or less domed in the vertical, making things just a bit more interesting.

This is a minor update to have a little more description for the PyPI package repository.
Please refer to release v2.0 for detailed information on updates relative to <v2.

ParaView Update

Due to the latest ParaView update to version 4.2, a few filters have now different parameters. The examples have been adapted to this. Unfortunately, this means that the updated examples will not run in earlier versions of ParaView, and vice versa.
However, you are strongly encouraged to update to the latest ParaView version anyway, so this should not be a major issue.

Re-naming

`atmos_grids` is now `grids`, and `atmos_basic` is now `basic`. This is due to the fact that this package has become much more general.
`Add?Plane()`, with ?=X,Y, or Z, has been consolidated into one function called `AddGridPlane()`.
`Add?Label()`, with ?=X,Y, or Z, has been consolidated into one function called `AddGridLabel()`.

Re-arrangement

`Lin2Log()` and `BoundAspectRatio()` have been moved from `atmos_basic` to `atmos_grids` (or rather to `grids`): This is where they belong and are used.
Also, `pv_atmos.basic` and `pv_atmos.grids` can now be imported completely independently. This is a big step forward in terms of installing `pv_atmos` as a python module.

New functions

Several important functions have been added to `pv_atmos.basic`:

Make3D

If you happen to have a 2D file (say, longitude latitude), which contains a field that should rather be a third dimension (say, ocean depth), then Make3D will do this for you. Simply feed the function with the name of the variable, and the axis along which it should be expanded, and you're done.
As everything, works with aspect ratio manipulation and logarithmic coordinates.

Some smaller changes are:

TransformCoords

Added a function to perform aspect ratio and/or logarithmic transformations of the coordinates. This makes it unnecessary to add an if-statement to check if it's logarithmic or not.

Sphere2xyz

Converts spherical geometry (radius, lambda, phi) into Cartesian coordinates (x,y,z). Useful for placing any object (label, camera, etc.) onto a spherical object.
This function also computes the normal along the radial direction, which can be fed to a camera, or to orientate any object perpendicularly to the surface of the sphere.

xyz2Sphere

The inverse function of Sphere2xyz. Given Cartesian position, compute the radius and spherical angles.