AE: Move commands from 1217.mac into andy_run.mac so that I know everything I have set is in one place. Also run for 100 events
AE: Use the gam_tgt particle generator
AE: Specify the "target" PositionMode and handle it in PrimaryGeneratorAction
AE: Want to be able to visualise with a macro
AE: Put in a few visualisation commands
AE: Add *~ to .gitignore
AE: A few more visualisation commands and print the final visualisation to a file
AE: Some more changes to my input macros
AE: First attempt at checking that an initial primary is inside the target
AE: Don't track secondaries to see if the "target" option works (it doesn't)
AE: Undoing my changes to PrimaryGeneratorAction considering it doesn't work
AE: Redoing the changes I made previously. I think there's a way to do this by looking at the material. Revert "AE: Undoing my changes to PrimaryGeneratorAction considering it doesn't work"

This reverts commit 0999d1b4fd7bf31f71bf558be17887635ff64ff8.
AE: Can now specify target as the position mode. This should solve issue #6
AE: Put a spread on the position so that all the photons are not produced at the same point
AE: Put the target back in the geometry
AE: Don't want to track so verbosely anymore
AE: Draw everything now
AE: Finishing this feature. Merge branch 'feature/AE_position-mode-target-option' into develop