Minor fixes, dead code removal, and coding policy fixes.

* 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.

common/common_plotGERBER_functions.cpp

@@ -44,8 +44,6 @@ void GERBER_PLOTTER::set_viewport( wxPoint aOffset, double aScale, bool aMirror
  */
 bool GERBER_PLOTTER::start_plot( FILE* aFile )
 {
-    char Line[1024];
-
     wxASSERT( !output_file );
     final_file  = aFile;
 
@@ -59,9 +57,9 @@ bool GERBER_PLOTTER::start_plot( FILE* aFile )
     if( output_file == NULL )
         return false;
 
-    DateAndTime( Line );
     wxString Title = creator + wxT( " " ) + GetBuildVersion();
-    fprintf( output_file, "G04 (created by %s) date %s*\n", TO_UTF8( Title ), Line );
+    fprintf( output_file, "G04 (created by %s) date %s*\n",
+             TO_UTF8( Title ), TO_UTF8( DateAndTime() ) );
 
     // Specify linear interpol (G01), unit = INCH (G70), abs format (G90):
     fputs( "G01*\nG70*\nG90*\n", output_file );