fixing upgrade bug related to .ctl (ctl_file) files. First of all, don't offer ctl files when upgrading (ok, we should make this possible if we need it). Second of all, use the ctl file selections the user actually made when choosing files to source (in proc apm_package_install_data_model)
bug 335 - making sure it's possible to install from .apm files again. The UI needs improvement. Robustness could also be improved. May need to handle the case when there is a later version of a package in the packages directory than in the apm_workspace dir