Specifying --filter-x a second time overrides the first provision

[pvandyken]

In my workflow, I tend to save my (usually very long) snakebids calls to an executable file. I leave a $@ variable at the end of the call so I can add whatever other arguments to the call I may need. Thus, I'll often have a --filter-x argument provided in the file, but if I provide a modifying --filter-x in my actual call, the first --filter-x gets overridden

I would say additional provisions of filter should modify previous provisions: new filters are simply added, previously specified filters are overwritten.