IVE: Update Filesystem on implementation change

In function properties dialog in the "Implementation" tab, react on changes:

On The Filesystem:

• there is no implementation yet, user chooses "Add implementation" => prompt for name ("default" by default) and select language from the list. Set it in the model as it is currently, so that the AADL file will be generated the same way (but store the name in the xml model) Call "make skeletons" to generate the function skeletons. It will put the code at the same place as now.
• there is already one or more implementation, and user chooses "Add implementation" if the name of the current implementation was e.g. "default" and language was "SDL" then move the content of work//SDL into work//implem/default/ (recursively) then set the newly created implementation as the current one make skeletons -> user can edit the code of the new implementation which is the default one
• user changes the current implementation make the move of the current implementation as in option 2 then move the implementation from /implem/newCurrent/language to /
• user deletes an implementation that is not the current one prompt "Are you sure?" delete /implem/
• user deletes the current implementation delete / if there are no implementation left, stop there otherwise take the first one in the table and set it as new default (execute steps of 3))