While we are at it:
- Rename some variables to more meaningful names
- Reuse some common consts from a header instead of redefining them.
Change-Id: I75c4248cb75aa54c52111686f139b096dc119328
Change the name of source files to replace "vpx" with "aom".
Change occurences of "vpx" in the code to "aom".
Change-Id: I002c0eaa2c350cf1a895bf01bea5788c61328027