ldpc_dec modified to read in half frames and perform FEC frame sync, cohpsk and unit...

ldpc_dec modified to read in half frames and perform FEC frame sync, cohpsk and unit tests modified to work with non-diversity, next step verify cohpsk with AWGN and test on cmd line with LDPC decoder

git-svn-id: https://svn.code.sf.net/p/freetel/code@3072 01035d8c-6547-0410-b346-abe4f91aad63