Make sure ./downloads directory exists before trying to install downloaded kexts

minor refactoring in SSDT-PNLF

Add 10.13 boot graphics glitch patch; disable 10.12+ boot graphics patches by default (already by Lilu.kext+IntelGraphicsFixup.kext)

Rename SSDT-NVDA to SSDT-DGPU; fix a typo in install_downloads.sh

minor changes to download.sh, patch_hda.sh, & update_config.sh

cleanup config_install.plist; add Inject/NVidia=true for bogus class-code/etc properties

Minor changes to new patch_hda.sh

few changes to install_downloads.sh

few changes to new patch_hda.sh script

rewrite patch_hda.sh; inject audio PinConfigs via CodecCommander.kext; fix typo in install_downloads.sh

add AppleBacklight profile patch & use pre-built AppleBacklightInjector.kext

sudo not needed for new mount_efi.sh

Use new friendly ACPI/DSDT/Fixes names; cleanup config.plist

cleanup config.plist (remove old patches); cleanup install_downloads.sh

Add disabled #a country patch