Add Schechter1D model example plot and references
Add Schechter1D model example plot and references

astropy/astropy,saimn/astropy,larrybradley/astropy,mhvk/astropy,lpsinger/astropy,StuartLittlefair/astropy,lpsinger/astropy,StuartLittlefair/astropy,astropy/astropy,mhvk/astropy,StuartLittlefair/astropy,lpsinger/astropy,saimn/astropy,astropy/astropy,pllim/astropy,mhvk/astropy,StuartLittlefair/astropy,larrybradley/astropy,pllim/astropy,pllim/astropy,pllim/astropy,larrybradley/astropy,larrybradley/astropy,saimn/astropy,larrybradley/astropy,mhvk/astropy,saimn/astropy,astropy/astropy,StuartLittlefair/astropy,lpsinger/astropy,pllim/astropy,astropy/astropy,mhvk/astropy,saimn/astropy,lpsinger/astropy