Add front matter to Events pages.

...pentry_open_science_grid_workshop_unl_january_6_8_2016.md

content/events/software_carpentry_workshop_setup.md

...vents/software_carpentry_workshop_unl_january_5_6_2017.md

...vents/software_carpentry_workshop_unl_january_8_9_2015.md

...events/software_carpentry_workshop_unl_july_15_16_2015.md

...vents/software_carpentry_workshop_unl_march_20_21_2015.md

...vents/software_carpentry_workshop_unl_march_27_28_2017.md

...ents/software_carpentry_workshop_unl_november_5_6_2015.md

...vents/software_carpentry_workshop_uno_april_22_23_2015.md

...events/software_carpentry_workshop_uno_july_14_15_2016.md

content/events/supercomputing_mini_workshop_2012.md

...t/events/supercomputing_mini_workshop_february_27_2013.md

content/events/unk_linear_algebra_feb_28th_2017.md

...nt/events/unl_numerical_analysis_class_august_5th_2016.md

content/events/unl_r_for_biologists_class_march_8_2017.md

content/events/unl_stat802_january_23rd_2017.md

content/events/unl_stat_802_fall_2017.md

content/events/unl_stat_850_fall_2017.md

content/events/unl_stat_850_fall_2018.md

content/events/unl_stat_950_fall_2017.md