MFDv5: check whether --SFTWindowType matches header of --noiseSFTs

Left over from CW/software/lalsuite#84 as a longer-term nice-to-have feature request for MFDv5:

@rodrigo.tenorio : add a feature to check whether SFTWindowType and noise SFTs' window function are the same.
presents an additional problem: The window function is not an entry in the SFT header; although one could try to recover such information from the command line arguments used to produce an SFT, such information is not always present.

@evan-goetz : If MFD can do all the hard work internally to figure out what window was used for the noise SFTs and apply that to the signal to be added, then that is an even better solution. This seemed like a much bigger job, so with MFDv4, I settled on a similar solution as option 2. As noted, it's hard to figure out what window was used, so that was another reason I didn't implement it. Reinhard and I had thought about having some more clever xml header or dictionary, but we didn't get that far and we had other things to worry about in 2012.