After 3 failed saves, offer to disable safe saves

* User is prompted to disable safe saves after three failed attempts
* Completely retooled basic settings to group settings logically
* Added setting for "atomic saves"

src/core/Config.cpp

@@ -115,6 +115,7 @@ void Config::init(const QString& fileName)
     m_defaults.insert("AutoReloadOnChange", true);
     m_defaults.insert("AutoSaveOnExit", false);
     m_defaults.insert("BackupBeforeSave", false);
+    m_defaults.insert("UseAtomicSaves", true);
     m_defaults.insert("SearchLimitGroup", false);
     m_defaults.insert("MinimizeOnCopy", false);
     m_defaults.insert("UseGroupIconOnEntryCreation", false);