#3 DCD trajectory Reader

[santanu chatterjee]

DCD Trajectory reader in ProtoMol can't read DCD files produced by NAMD 2.6 (NAMD folks have modified DCD file format slightly from 2.6). I wrote a modified DCD trajectory reader to fix this problem. However, I am not sure if it can still read the DCD files generated by ProtoMol. We need to merge these two DCD readers.