[Core] Serialize LogicalName for non-EmbeddedResource items

BXC19470 - Resource ID changes made in the Properties pad not reflected
in the csproj
Fix bug 20005 - Gtk access in the background thread
Show a warning message when opening a solution that is already opened
Merge pull request #557 from knocte/master

[FindInFiles] Add a new "Project" column in results
[FindInFiles] Fix typo in last commit for BXC#17426