Adding the 'mandb' command for Linux + taking first any installed markdown-extended
Renaming the whole thing

- "dev-tools" becomes "devtools"
- the bash-lib has to be updated
- new "md2man" action script
Updating the bash-library
New version 1.1

- all "dev-tools*" is renamed in "devtools*"
- new "md2man" action
- new MarkdownExtended binary name "markdown-extended"