allow setting a larger node width and smaller zoom

[ekg]

Many of the graphs that I want to apply Bandage to visualize are larger than 10M in length. As a result, they are hard to render within the node width limits that are given. They look like this:

This is with --nodewidth 1000.

I've tried to patch bandage to allow a larger node width, and this works fine in the UI, but I can't seem to figure out how it's set in the command line. It does not seem they are set in the same place but I may be missing something.

(Also, I can't figure out how to make a static compilation so that I can run the patched version on a remote server where setting up Qt will be difficult, but this is another issue.)