Improve plotting of detection border

[MatthewWhiting]

Currently the detection borders are plotted in the annotation files as a series of 1-pixel-long lines that make up the outer border of the detection.

However, there are two problems with this:

1. CASA viewer cannot handle this at the moment. It can do polygons, but not lines.
2. The annotation files can get a bit large.

A solution would be to do them in a "join-the-dots" fashion - ie. make use of the fact that polygons are accepted by casaviewer. This way we only give the vertices, in order around the border, which should also make the annotation files smaller.

[MatthewWhiting]

Done in [1293].

We take the list of edge elements and extract the edge vertices one by one. Starting with one of them, we search through the list to find the next one in order and progress through until we get back to the start. This can generate multiple vertex lists per object, for instance if there is a separated island or pixels joined by a corner only.

The two parts of the code that use this (drawing outlines on the moment maps and writing the annotation files) have been updated, with the CASA region file overhauled a little at the same time (removing the box annotation).

I've also updated the verification results, so that the .ann and .reg files match.

Closing ticket.

[MatthewWhiting]

Reopening this, as the code itself could do with a bit more work. Fix the doxygen comments at the start of getVertexSet, and remove the old instances of vertexSet, as these are no longer used.

[MatthewWhiting]

This was done in [1353], so closing ticket.