Redesign shaders

Todo:
- [x] 1. Move resources that contain the actual shaders' code
- [x] 2. Delete now obsoleted shader-related settings, write the migration handler
- [x] 3. Update the installer and portable version packer
- [x] 4. Remove mpc-hc shader editor, it hardly has any use when the shaders are in separate external files
- [x] 5. Improve mpc-hc shader selector from single panel to dual panel view (from [this](https://www.dropbox.com/s/so19a0fzbbhsxlg/mpc_hc_shaders_old.png) to [not quite, but something like this](https://www.dropbox.com/s/f8y5u4wdsipikyw/mpc_hc_shaders_new.png)). Maybe add a new property page in Options dialog for it?
- [x] 6. Implement shader-selection presets
- [x] 7. Implement shaders auto-recompilation based on filesystem notifications
- [x] 8. Implement shaders debug window (compilation output now present in shader editor is planned to go there)
- [x] 9. Add .hlsl to the list of checkyear extensions in pre-commit hook.
- [x] 10. Back up shader code before removing it from config.
- [x] 11. New command-line args.
- [x] 12. Add first-run message box about auto-recompilation to Debug Shaders window.

@XhmikosR, @Underground78, @Armada651 I need your opinions on 4, 5, 6.