ENH: refactored buffer with cleaner separation of different lock types.  Also reworked reserve function for lockfree buffer.  Tests passing at 10 iterations.
ENH: refactored buffer with cleaner separation of different lock types.  Also reworked reserve function for lockfree buffer.  Tests passing at 10 iterations.

ParBLiSS/kmerind,ParBLiSS/kmerind,ParBLiSS/kmerind,ParBLiSS/kmerind,ParBLiSS/kmerind,ParBLiSS/kmerind