put past events in folders based on the year of the event

content/events/2012/_index.md

++++
+title = "2012"
+description = "Historical listing of various HCC events for the year 2012."
+weight = "30"
++++
+
+Historical listing of HCC Events
+----------
+
+{{% children %}}

content/events/2012/desktop.ini

+[LocalizedFileNames]
+supercomputing_mini_workshop_2012.md=@supercomputing_mini_workshop_2012,0

content/events/2013/_index.md

++++
+title = "2013"
+description = "Historical listing of various HCC events for the year 2013."
+weight = "30"
++++
+
+Historical listing of HCC Events
+----------
+
+{{% children %}}

content/events/2013/desktop.ini

+[LocalizedFileNames]
+hcc_condor_workshop_2013.md=@hcc_condor_workshop_2013,0
+hcc_matlab_workshop_2013.md=@hcc_matlab_workshop_2013,0
+hcc_mpi_workshop_2013.md=@hcc_mpi_workshop_2013,0
+june_2013_osg_workshop.md=@june_2013_osg_workshop,0
+supercomputing_mini_workshop_february_27_2013.md=@supercomputing_mini_workshop_february_27_2013,0

content/events/2014/_index.md

++++
+title = "2014"
+description = "Historical listing of various HCC events for the year 2014."
+weight = "30"
++++
+
+Historical listing of HCC Events
+----------
+
+{{% children %}}

content/events/2014/desktop.ini

+[LocalizedFileNames]
+august_2014_uno_hcc_workshop.md=@august_2014_uno_hcc_workshop,0
+july_2014_bioinformatics_workshop.md=@july_2014_bioinformatics_workshop,0
+june_2014_bioinformatics_workshop.md=@june_2014_bioinformatics_workshop,0
+october_2014_hcc_workshop_college_of_engineering.md=@october_2014_hcc_workshop_college_of_engineering,0
+september_2014_hcc_workshop_earth_and_atmospheric_sciences.md=@september_2014_hcc_workshop_earth_and_atmospheric_sciences,0

content/events/2015/_index.md

++++
+title = "2015"
+description = "Historical listing of various HCC events for the year 2015."
+weight = "30"
++++
+
+Historical listing of HCC Events
+----------
+
+{{% children %}}

content/events/2015/desktop.ini

+[LocalizedFileNames]
+hcc_fall_kickstart_2015.md=@hcc_fall_kickstart_2015,0
+software_carpentry_workshop_unl_january_8_9_2015.md=@software_carpentry_workshop_unl_january_8_9_2015,0
+software_carpentry_workshop_unl_july_15_16_2015.md=@software_carpentry_workshop_unl_july_15_16_2015,0
+software_carpentry_workshop_unl_march_20_21_2015.md=@software_carpentry_workshop_unl_march_20_21_2015,0
+software_carpentry_workshop_unl_november_5_6_2015.md=@software_carpentry_workshop_unl_november_5_6_2015,0
+software_carpentry_workshop_uno_april_22_23_2015.md=@software_carpentry_workshop_uno_april_22_23_2015,0