Release v0.4.0

- Multiple tabs (for editing libraries)
- Recognize constants like DisplayMode.Pa
- Enable autocomplete by default (also fix autocomplete for instructions)
- Custom window to load libraries (including full-text searching)
- Never enforce line/byte limit for library code
- Allow switching between IC10/plain text (useful for notes)
- Export button in library tab reads "To MB" and applies it to Motherboard tab
- Vim: search commands /, ?, *, #, n, N
- Close tab with middle mouse button
- Case-sensitive autocomplete
- Fix labels highlight color
- Fix throwing items on close (because Q key is still pressed)