removed swc events from 2015, removed etherpad reference from fall kickstart

content/events/2015/hcc_fall_kickstart_2015.md

.../2015/software_carpentry_workshop_unl_january_8_9_2015.md

...s/2015/software_carpentry_workshop_unl_july_15_16_2015.md

.../2015/software_carpentry_workshop_unl_march_20_21_2015.md

...2015/software_carpentry_workshop_unl_november_5_6_2015.md

.../2015/software_carpentry_workshop_uno_april_22_23_2015.md