* Use version of DateAndTime that returns a wxString and delete the
  version that takes a char* as it is no longer required.
* Merge StrNumICmp() and StrLenNumICmp() into StrLenNumCmp() to create a
  single function for comparing strings with integers and remove a lot
  of duplicate code.
* Remove unused strupper from string.cpp.
* Use wxArrayString for sorting the EDA_LIST_DIALOG contents.