Skin Restorer

Added

• Added versioning and migration system for config and skin data files
• Added join.skipRefreshProviders config option to skip skin refresh on join for specific providers (see wiki)
• Added request.userAgent config option for customizing the HTTP user agent (see wiki)

Changed

• Reorganized config structure into join, request, and autoFetch sections (automatically migrated from old format)

Fixed

• Fixed bundled player info remove and update packets causing skin update issues (fixes #96)