Trying to fix freefem++ artifact build issues.
Updated the README
Added a Contributing.md file (first commit)

Added a PortingWorkflow.dot file, which will describe the full porting workflow
Added a new header description for AAROC contributions - outside of SAGrid
First draft of dot file for the porting workflow.
Merge branch 'master' of https://github.com/SAGridOps/SoftwareInstallation

Conflicts:
	README.md
	math/freefem++/generic/build.sh