- Users table model renamed to UsersTableModel- causes linker conflict

with class TableModel in accomodation plugin.
- Edit record dialog is now screen centered.
- Plugin tabs in application main window are now closable.

core/users/usersui.cpp

@@ -3,7 +3,7 @@
 
 UsersUi::UsersUi(QWidget *parent) :GridForm<User>(parent)
 {
-    setTableModel(new TableModel);
+    setTableModel(new UsersTableModel);
 }
 
 UsersUi::~UsersUi()