Set minimum width on right pane to avoid overlap

[Kukanani]

Before this fix, the minimum width of the right pane was 0, which would result in the following at narrow widths:

After this fix, the panel has a minimum width to prevent this behavior (this is the narrowest the panel resizes):

[cottsay]

This solution mitigates the problem in most common circumstances, but it doesn't really solve the problem. For example, nested parameter groups like tabs still suffer.

I found that the most expedient solution which would work for all of the parameter layouts is to remove the minimum size from the parameter name QLabel, which was set to 100px. When you make the window really small, the value editing widget still jumps over to where the label used to be shown, but the label disappears correctly instead of overlapping.

I find that this might be a better solution than enforcing minimum sizes on the layout which might be a problem for small displays like netbooks used to run robots.

Please take a look at #14 and let me know what you think.