Merge jung-kurt#310: fix utf16 in bookmarks by SuddenGunter

Merge branch 'SuddenGunter-bookmarks-utf16'

Use strings.Replace instead of strings.ReplaceAll to user older versi…

…ons of Go

Use strings.Replace instead of strings.ReplaceAll for older library s…

…upport

Merge from v2: Escape spaces in font family string to comply with PDF…

… standard

Escape spaces in font family string to comply with PDF standard

Restore go.mod replace directive

Merge Strikeout: use 'S' as styleStr jung-kurt#299 by Rjinswand

Add Joe Westcott's image storage optimization

Merge branch 'Rjinswand-strikeout'