Vecps Code Maintenance: vecps_plotter Rework

[edbarriga]

This is a major rework for the vecps_plotter program. The code is now more modular and requires less user modification, reducing the need for recompilation. To highlight some of the most important changes:
-The code now parses the info from the fit file into an "amplitude registry" where all the important info is stored
-The user no longer needs to hard-code the amplitudes to be plotted. Now, every amplitude in the fit file will be plotted
-The code has logic that avoids nonphysical amp and sum combinations that would have produced an empty histogram
-The code now accepts user input that was hard-coded such as: running over a single reaction, plotting acceptance correction histograms, plotting background histograms, and producing only ROOT or txt output
-The code now has a rudimentary CSV output

PS I plan to add two features before merging: adding parameters to the text-based output and a helper function in VecPsPlotGenerator to avoid the need to modify the plotter when adding histograms.

[gluex]

Test status for this pull request: SUCCESS

Summary: /work/halld/pull_request_test/halld_sim^vecpsCodeMaintenance/tests/summary.txt
Logs: /work/halld/pull_request_test/halld_sim^vecpsCodeMaintenance/tests/log

Build log: /work/halld/pull_request_test/halld_sim^vecpsCodeMaintenance/make_vecpsCodeMaintenance.log
Build report: /work/halld/pull_request_test/halld_sim^vecpsCodeMaintenance/report_vecpsCodeMaintenance.txt
Location of build: /work/halld/pull_request_test/halld_sim^vecpsCodeMaintenance