OggOpus draft updates.

Bump version and date for draft-ietf-codec-oggopus-03 submission.

Move more text into figure pre/postamble to fix rendering issues
in the xml2rfc html output. These need to be manually re-indented
in the txt output before submission. :(

Fix resampling frequency choice algorithm, which was missing a word.

Fix some spelling and make some minor enphasis changes.
Adds missing license for arm2gnu.pl
Fixes an aliasing bug in the MDCT when the frame size isn't a multiple of 4.

In that case, the yp0 and yp1 ended up aliasing for the last element,
despite being marked as restrict.

Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>
arm: Use the UAL syntax for instructions

This is required in order to build using the built-in assembler
in clang.

Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>
Fixes encoder/decoder classification of ctl() requests.

Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>