Updated sensitivity figure 3.3 in section 3.4.1

Updated section 4.2.2.3 (on cross map) to include the mode changes recently incorporated -- availability of selectable cross step size.

Changed figure 6.2 to new HSpot front end

Updated section 6.2.1.1 to indicate new save and load facilities from instrument and frequency settings for HIFI

Updated section 6.2.2.3 to include information on storage of time estimates in AOR files

Changed figures 6.19, 6.27 and 6.32 to show updated front end for HIFI HSpot instrument settings.