Fix reference to libspeexdsp in speexnoisesup.

git-svn-id: https://svn.code.sf.net/p/freetel/code/codec2-dev@1742 01035d8c-6547-0410-b346-abe4f91aad63
Added Win32 msys/mingw cmake build instructions

git-svn-id: https://svn.code.sf.net/p/freetel/code/codec2-dev@1743 01035d8c-6547-0410-b346-abe4f91aad63