changed the CompareTo comparison from ">= 0" to "< 0"
fixed duplicate listing of installed extensions
- one case was implemented wrong: when installing a downloaded extension file via double click or drop on the main form or menu entry Open File, the installed pack was not removed (remove method was called with the new package as parameter)
Merge branch 'BUG-4215-MPEInstaller_lists_extensions_that_have_been_updated_without_uninstall_multiple_times'
Merge branch 'BUG-4315-MPEI_incorrectly_installs_linked_extensions_when_version_is_lower'