Comment 4 for bug 1102410

I've changed the title of the bug to be more descriptive as to what was actually fixed here. The dash blur now uses linear sample interpolation to take fewer texture lookups with similar accuracy to a normal gaussian algorithm. That is one potential speed-up of the dash blurs, but there are other bottlenecks which are also relevant. "Speed up the dash blur" is too vague and may lead to a situation where the bug is reopened again an necessary number of times.