Extract jazzy config to .jazzy.yml. Use "fullwidth" theme.

.jazzy.yml

@@ -0,0 +1,11 @@
+author: "Gwendal Roué"
+author_url: "https://github.com/groue"
+github_url: "https://github.com/groue/GRDB.swift"
+github-file-prefix: "https://github.com/groue/GRDB.swift/tree/v3.7.0"
+copyright: "© 2015-2019 [Gwendal Roué](//github.com/groue) under [MIT license](//github.com/groue/GRDB.swift/blob/master/LICENSE)."
+module: "GRDB"
+module-version: "3.7"
+root-url: "http://groue.github.io/GRDB.swift/docs/3.7/"
+hide_documentation_coverage: true
+theme: fullwidth
+use_safe_filenames: true

Makefile

@@ -400,13 +400,7 @@ doc:
 ifdef JAZZY
 	$(JAZZY) \
 	  --clean \
-	  --author 'Gwendal Roué' \
-	  --author_url https://github.com/groue \
-	  --github_url https://github.com/groue/GRDB.swift \
-	  --github-file-prefix https://github.com/groue/GRDB.swift/tree/v3.7.0 \
-	  --module-version 3.7 \
-	  --module GRDB \
-	  --root-url http://groue.github.io/GRDB.swift/docs/3.7/ \
+	  --config .jazzy.yml \
 	  --output Documentation/Reference \
 	  --xcodebuild-arguments -project,GRDB.xcodeproj,-scheme,GRDBiOS
 else