Updated LDraw tools for parts authors: Selector and SymSplitter

[Philippe Hurbain]

A new version of Selector (V1.2) is available:

• Bug correction: using discolor (-d, -d+) previously implied -m option
  
• Bordering condlines are no longer selected if -b option is specified.
  
• Condlines and edge lines are now sorted separately when -s option is specified.
  

A new version of SymSplitter (V1.2) is available, introducing new options:

• -x++..-z-- are similar to -x+..-z-, but use an offset parameter to be able to use any plane in main directions, not just origin planes. "-x++ 0" is the same as "-x+".
  
• -i inverts direction of split. No need to invert winding of elements in splitter file. This is active also for main plane splits, so -i -x+ is the same as -x-
  
• -d0 options deletes nothing. This allows to snap elements of a file to splitter plane(s). Warning: splitter planes are infinite, so snapping may occur in areas far form the area you want to modify!