#901 NullPointException when resolving in bndrun file 

The code assumed the directory was a project so it could find the repositories. Now it uses the information from location of the bndrun file and the Eclipse workspace info.
[central] Some extra convenience methods for getProject(IProject) and isCnfChanged
[resolve] #901 better move the getting of the project inside the place where we use it since it is null in other cases.