Made the code less ambiguous, removed compiler warning, no functional change

ntru_crypto_ntru_encrypt.c: In function ‘ntru_crypto_ntru_decrypt’:
ntru_crypto_ntru_encrypt.c:586:28: warning: operation on ‘*(ringel_buf2 + (sizetype)((unsigned int)i * 2u))’ may be undefined [-Wsequence-point]
             ringel_buf2[i] = --ringel_buf2[i] & mod_q_mask;
                            ^
Improving Sample Program

Improved the sample program to check for correct decryption and dump data to screen and files
Removed include file which is not public
Merge pull request #14 from thesourcerer8/master

Improving the Sample Program