plot functions to fix - Githubissues

Fix/Update

[x] chl_pp (PP anomaly ratio blank)
[x] habs - blank plots for MAB (return null as not applicable for the MidAtlantic report)
[x] hms_landings - missing plots
[x] thermal_habitat_persistence. Add year as an argument so that plot can be made for current year
[x] bennet - requires plots for additional plot types (guild, total, total_guild)
[x] bennet - show data from 1982 (currently 1985)
[x] gsi has additional variable (add varName = western gsi)
[x] wind_revenue - add plottype to dosplay all species in same figure
[x] wind_port - add social justice icons to figure
[x] engagement - consistent colors across classes (Thanks to Abby)
[x] zoo_diversity - the mean hline is incorrect in NewEngland report
[x] wcr - errors for NewEngland (return a null object instead of error)
[x] wcr - post 2000 mean line to end in 2017
[x] seasonal_sst_anomaly_gridded - errors for MidAtlantic
[x] wind_dev_speed - label options
[x] aggregate_biomass - replace yaxis labels with a single y axis label
[x] use geom_gls in plot_exp_n
[x] abc_acl - adjust x axis labels for both plottypes so that years have no decimal
[x] comdat - all plots, start in 1982 to match Bennet index (currently 1985)