Added A Collapse icon button at the bottom of replies (#17)

- On Collapse, Scroll up to the original comment
- When expanded, show the add reply input automatically
- Click the icon button at the bottom left to collapse comments
- Added borders on the left and bottom to demarkade boundaries of
comments and their replies

Author: coolsam726

.gitignore

@@ -1,6 +1,7 @@
 .DS_Store
 .idea
 .phpunit.result.cache
+.phpunit.cache
 .vscode
 build
 composer.lock