v1.3 'Dargo'

This is mainly a bugfix release. I found some subtle problems that were messing up the contour plots. AGES cubes probably wouldn't have suffered too much from these,but they are now fixed. 

Other changes :


- Option to import contour maps as vectors (i.e. Blender's internal mesh format) rather than .png raster images. These give much nicer results. However, they can cause problems if you need to import very large/complex contour maps (plotting 100,000 vertices is easy, calculating where they should all go is not) so there's still an option to import them as images. If in doubt, import them as images first.

- Contour images limited to 3000x3000 pixels, preventing things from going haywire with large maps

- Field of view for RGB images now calculated based on the pixel scale of the HI cube (previously assumed 1' pixels). Warns user if pixels aren't square.

- Layer management GUI, allowing the RGB/flux/contour maps to be easily shown and overlaid

- Maps are now offset correctly from each other so they can be overlaid correctly

- Selection tool incorporated into the AnalyseFITS script as well as the ImportFITS script

- Maps created by the selected region are now deleted before new ones are created. This means that if you create a flux map for one region, then change its size and request another flux map, the old one is removed first.

- Layer 5 is enabled by default so that you can see regions you create (should have done this already !)

- Rudimentary error trapping. Error messages may not be meaningful or in English, but the script won't crash if something goes wrong any more (the SDSS features are an exception - sometimes the service times out rather than generating an error, in which case the script may still crash)

- After creating a map, the region(s) remain selected, rather than the map. This makes it easier to quickly create different maps for the same region.