improved popup behavior + added warning for replacing originals

-Closes #21 , modified execution error popups by giving users options on how to proceed. ignore, ignore all errors, or cancel execution.
-Closes #16 , added an additional popup warning the user about replacing files.
-Effectively closes #19 by giving the user the option to see every specific error via #21
-Fixed spelling error...

ProgramUI.java

@@ -310,7 +310,7 @@ public void cancelPopup(int converted) {
     public void warningReplacingFiles(){
         int choice = JOptionPane.showOptionDialog(this,
             "By continuing you will be replacing your original screenshots. This cannot be undone.\n"
-                + "Please press Cancel and change the behaivor settings if this was not intended.",
+                + "Please press Cancel and change the behavior settings if this was not intended.",
             "Replacing Files",JOptionPane.OK_CANCEL_OPTION,JOptionPane.WARNING_MESSAGE,
             null,null,null);
         if(choice != 0) {