Get some numbers on % and X increases in performance since last Christmas

perf_improvements.sh

git log --since 2016-12-25 --oneline | perl6 -e 'say lines().grep(/(\d+\.?\d*?)\%(" "|$)/).map({/(\d+\.?\d*?)\%(" "|$)/; ~$/[0]}).sort.join("\n")' > %_increase.txt
git log --since 2016-12-25 --oneline | perl6 -e 'say lines().grep(/(\d+\.?\d*?)x(" "|$)/).map({/(\d+\.?\d*?)x(" "|$)/; ~$/[0]}).sort.join("\n")' > x_increase.txt