better explain some parameters in the documentation

[aisbergde]

[-maxdet number]
Limit for when tables should be shown with details.

What details? What limit? Is it about the number of columns shown in the graphic?

[-desc description]
Add a description to the index page.

What is the index page?

[-renderer :rendererName]
Specify which renderer to use should be prefixed with ‘:’ example -renderer :cairo

are there other renderers available? Which?

[-degree 1 or 2]
Limit the degree of separation (1 shows less, 2 is default), 1 is a good option for large databases with lots of relationships.

what is the "degree of separation"? it is not at all clear what does in mean.