AirDC++ 4.00

What's new in this version:

Added:
- Extension tab for installing and managing extensions
- Include node.js extension engine in the updater and installer
- Add labels for event log messages
- Allow changing web server bind addresses from the settings, show a link to the Web UI
- Add an option to show user IP and country in chat (RoLex)
- Allow setting a custom temp file path via dcppboot.xml

Changed:
- Bind web server to localhost (127.0.0.1) by default
- Don't wait until the current file has finished completed when stopping hashing
- Don't allow adding bundle sources without a known hub
- Save application identifier in the settings file for more reliable future settings migration
- Improve handling of directory downloading errors

Fixed:
- Fix incorrect TTH data being added in hash store when shutting down while hashing is in progress
- Fix fetching the list of downloaded files for partial bundle sharing

Removed:
- Inbuilt check for missing/extra files (replaced with the airdcpp-release-validator extension)
- Inbuilt share monitoring (replaced with the airdcpp-share-monitor extension)
- Manual SFV checker (can be implemented with an extension)
- fulDC FTP logger (can be implemented with an extension)
- Support for migrating legacy XML hash databases from DC++ (or other compatible applications)