CmdLine: Provide more information on file conflict.

Eases #353.
Actually find the owning mod on file conflict.

Fixes #353.
Merge pull request #355 from KSP-CKAN/353_file_conflict

CmdLine: Provide better diagnostics on file conflict.
Merge remote-tracking branch 'origin/release-v1.0'

* origin/release-v1.0:
  Actually find the owning mod on file conflict.
  CmdLine: Provide more information on file conflict.