Build-wrap should check for the existence of dependencies in the project repository

[dirv]

Sometimes wraps get deleted or cleaned (for whatever reason). Build-wrap then fails with a lot of reference not found errors. It would be better to output an error such as

'Dependent package x was not found in the project repository. Please run update-wrap before building the project.'

[serialseb]

Do you mean the check should be in the msbuild tasks? If a dependency is not found (as opposed to just not having any assemblies to reference) we shoudl probably issue a warning in MSBuild.