Update to create a notification channel for SDK 26 and up#140

Closed

pauly815 wants to merge 2 commits intoNativeScript:masterfrom

pauly815:feature/android8-notification

Commits on May 8, 2018

updated to create a notification channel for SDK 26 and up
pauly815
committed

Commits on May 11, 2018

updated per reviewer feedback - added android declaration and created private method
pauly815
committed