batch mode

[cmagness]

this needs to be able to take multiple targets, multiple files, and multiple ion measurements and perform them all at once

[cmagness]

as discussed with @andrewjfox78, important key factors of this to consider as well are the case of encountering multiple x1dsums for the same dataset (this is referenced by #18). we discussed adding a column for rootnames associated with each measurement. i am also considering adding a column for program ID.

in order of priority:

• accepting multiple targets
• accepting multiple exposures from the same target AND different targets
• accepting multiple ion measurements