octave and C versions of modem in sync

git-svn-id: https://svn.code.sf.net/p/freetel/code/codec2-dev@1708 01035d8c-6547-0410-b346-abe4f91aad63
3D rotation code in freq offset test

git-svn-id: https://svn.code.sf.net/p/freetel/code/codec2-dev@1709 01035d8c-6547-0410-b346-abe4f91aad63