added possibility to use relative paths in projects.json

The use of relative paths in the projects json allows for using the mock
server as a dependency and thus allows it to be started by Grunt.js.
Updated README.md
Removed unneeded projects.json
Merge branch 'master' of https://github.com/jhadenfeldt/vi-mock-server
Merge pull request #1 from jhadenfeldt/master

Added possibility to use relative paths in projects.json and updated README.md accordingly