Upgrade EasySIMBL to v1.7.1

Hi! Let's give some love to EasySIMBL:
- Upgrade EasySIMBL to v1.7.1
- Remove unnecessary trailing slash from GitHub-hosted homepage url
  - Are there any style rules regarding urls normalization? It's trifle but with so amazingly detailed DSL documentation only this prevents my inner perfectionist from being completely happy ;)
- Change license to GPL
  - https://github.com/norio-nomura/EasySIMBL#license
- Add zap stanza
  - We certainly shouldn't remove the app's Application Support folder as it contains user manually installed plugins

Thanks for all of your hard work!