#57 installer: allow not to change installation path after ...

[Tuomas Kassila]

1. Installed beta-daisy gui version
2. After a try, I installed earlier current release,
and under installation installation application founded
earlier installed gui installation path (Ok)
3. But the installer make it impossible to change into
a new installation path!

[Romain Deltour]

This is on purpose: it was required that the installer made sure that two versions of the same application should not be installed.

The way to change the location is to uninstall the previous version and re-install to another directory.