Correction of various URLs (especially in the vignette)

v1.0.5

Correction of URLs in the vignette

Minor changes from v1.0 (in the vignette)

Canonical URLs are used now in the vignette. Also, a 'pkgdown' web site is available now at https://www.sciviews.org/svUnit/.

Stable version

.gitignore docs/ because the pkgdown site is now rebuild in the gh-pa…

…ges branch