the goal of this change is to convert rtcd.sh to perl as directly as
possible to allow for simple comparison. future changes can make it more
perl-like.
---
Linux
[CREATE] vpx_scale_rtcd.h
real 0m0.485s -> 0m0.022s
[CREATE] vp8_rtcd.h
real 0m4.619s -> 0m0.060s
[CREATE] vp9_rtcd.h
real 0m10.102s -> 0m0.087s
Windows
[CREATE] vpx_scale_rtcd.h
real 0m8.360s -> 0m0.080s
[CREATE] vp8_rtcd.h
real 1m8.083s -> 0m0.160s
[CREATE] vp9_rtcd.h
real 2m6.489s -> 0m0.233s