Explicitely specify Markdown extension for VM scripts Readme file
Add source hyperlinks in the VM readme
Fix codeblocks
Fix Readme to comply with documentation standards
Format variable names
Fix formatting issues

- Add break lines to long code blocks
- Create relative link to VM folder instead of using hardcoded URL
- Remove hardcoded version number for DL_LOC
- Unify utility scripts code block examples with the rest of the README
Merge pull request #689 from sbesson/vm_instructions

Fix VM installation instructions