Overriding and setting default values for homer processes

last cycle when you started creating files with the wrong monitor distances i put a fix in the mordred homer files

the homer distribution files are contained in

/usr/local/libisis/applications/matlab/

there are specific files used to set up the MERLIN instrument in the MERLIN directory

in the case where there is incorrect information in the rawfile which has been generated we can populate detector and spectra information from a nexus file. Of course creation of this file is another issue.