Added cmd option to add credentials

With `paket config add-credentials http://dummy` credentials will be added
to the user-config file.
Dogfood new lockfile format
added docs for add credentials
Merge pull request #458 from yannisgu/addCredentials

Added cmd option to add credentials
Merge branch 'master' of https://github.com/fsprojects/Paket
RELEASE_NOTES
draft on simpify
rop version of simpify
Handling every possible error in Simplify with ROP
cleanup
rop strangler for Convert from nuget