ArgumentStack fixes, Sponge update
- Fixed some ArgumentStack#of() methods not respecting quotes and joining strings into one.
- Added ArgumentStack#empty()
- Fixed Sponge implementation
- Allow response types of java.util.Optional
- Optimize CommandPath#getCategoryPath()
- Pass ArgumentStack#asImmutableView() to command conditions
- more fixes
Full Changelog: 1.2...1.3