Split VM from virtual container detection and add systemd-nspawn detector.
Add .gitignore.
Tune .gitignore.
Fix .gitignore.
Fix warnings using undefined values.
Add imvirt parameter to select container or machine detection.
Fix: Allow escaped quotes in lspci output (reported by Martin von Wittich <martin.von.wittich@iserv.eu>).
Update copyright and increase version to 1.0.0.