Bug 1042967 filter filenames before loading the file

i'm talking about the [comment you also removed](https://github.com/mozilla/addon-sdk/pull/1562/files#diff-06eb2f9c0d628b9966fb043303fd3b84L107) which describes when a filter function might be called with an empty `name` argument. 

i don't think that comment, and that behavior, and thus your condition `!(name && filterNameRegex)` applies anymore. 

with old code, calling the filter function without the `testname` second argument would filter only based on the file name regex. but with your split of that logic into two separate functions, `testFilter` should never be called with an empty `name` argument (if my understanding is correct).

(sorry if that's still unclear, i tried my best at this english thing.. ;)