Major improvements and fixes:
## Bootstrap-datepicker Integration
- Fix DPGlobal undefined error in date input
- Remove conflicting bdatepicker alias that was causing noConflict errors
- Add graceful error handling for missing bootstrap-datepicker dependency
- Implement proper initialization sequence for DPGlobal API
- Position datepicker above input with improved UX styling
## Select2 Integration & Compatibility
- Fix select2 integration with Select2 v4.1.0-rc.0
- Resolve issue where select2:select event fired but value didn't update
- Add event handler to manually update select2 value on selection
- Fix webpack build inconsistency between demo and standalone builds
- Remove redundant npm dependencies from demo (bootstrap-datepicker, select2)
- Implement proper Select2 v4 API usage for value setting
## Build System Improvements
- Fix webpack configuration to properly handle CSS imports
- Remove CSS file copying for npm dependencies, use webpack imports instead
- Ensure consistent input type registration across all build targets
- Clean up build output and remove debugging code
## Demo & Testing
- Update demo to use webpack source build for consistency
- Add comprehensive error handling and user feedback
- Clean up all debugging console output
- Improve demo page descriptions and usability
## Technical Fixes
- Fix 'Unknown type: select2' error in demo build
- Resolve value change detection preventing save operations
- Implement savenochange option for better UX
- Remove deprecated jQuery UI conflicts and aliases
- Update to modern webpack and build practices
