merge_source_list creates a master list of sources detected
from a list
of observations which have been processed to the point of a creating
an emldetect source list. Sources are compared and those within 
of each other have the one with the lower flux thrown out. It assumes
that the source detection has been in two bands, 0.4-1.25 keV and
2.0-7.2 keV, which can be produced by cheese-bands in the default mode.
Warning and requirements: merge_source_list is part of the esas package integrated into SAS, but it is limited to work within the esas data reduction scheme. This is specially true wrt the structure and names of the input files. In particular, merge_source_list assumes that other tasks from the package, mos-spectra / pn-spectra and cheese-bands have been successfully run for the lists to be used.
