Split DCT into two files, one for greyscale
Fixed DCT

It was never broken in the first place! It just turned out that the new
Python function for measuring how well it perform was making it look
worse than it actually is. By using my old Matlab function and comparing
at the binary level, it is evident that the DCT steganography is
actually quite successful.
Tidied up bin and str conversion functions
Removed mysterious X file
Merge pull request #2 from marbsydo/develop

Develop