Autoremoving end-slash from JCommune URL

1. Login in Admin Panel
2. Go to Components
3. Right-click on Forum Component
4. Set URL address to http://localhost:8080/jcommune/
5. Now JCommune notification about deleting smth will fail, because requestes will be like: DELETE http://localhost:8080/jcommune//branches/1, so JCommune respondes 500 status code. (because of double slash)

So after step 4 we need to auto remove last slash, so when user will set url to http://localhost:8080/jcommune/, before saving it will auto-changed to http://localhost:8080/jcommune