Whitespace

Replace all tab characters with 4 spaces, and fix indentation.
update-checksums.sh: Save temporary files in /tmp
Remove PKGBUILD.bak from gitignore
update-checksums.sh: Group filename variables at the top
update-checksums.sh: Rename SCRIPT_NAME to SED_SCRIPT_NAME
update-checksums.sh: Remove tmp dir with -c option
update-checksums.sh: Save temporary files in /tmp
update-checksums.sh: Add -f flag to makepkg --verifysource
Do not use btsync-wrapper on system-wide service

It's not necessary since /etc/btsync.conf is included in the package and
should therefore always exist. If it doesn't, then that means the system
administrator deleted it somehow, and that makes it their problem. ;)
Release 1.1.70-4

Changelog:
- Do not use btsync-wrapper on system-wide service