Package install overwrites existing files

If a package contains files already installed by other packages, but with different content, those files will be overwritten with the new content.

Since we have a package file hash feature, we should be able to detect if the file will be overwritten and create an error. Using --force will install the new package essentially leaving the existing package broken, but if --force is not used, it should not continue the installation.

If the installing package contains files that another package also has, but with same content (same hash), then installation can go ahead installing the files. This will often be the case for items in the 'Dependencies' folder.

A good example of this is when installing Editor CE on top of Editor.

Also Timing Analyzer and Results Viewer both install oxyplot of the same version.