changelog
    
    
    - Thu, 15 Mar 2018 10:46:46 +0200
 
    - by Teemu Piippo <teemu@hecknology.net> [Thu, 15 Mar 2018 10:46:46 +0200] rev 1285
 
    - added signal emissions
 
    - Wed, 14 Mar 2018 12:18:52 +0200
 
    - by Teemu Piippo <teemu@hecknology.net> [Wed, 14 Mar 2018 12:18:52 +0200] rev 1284
 
    - moved emit calls
 
    - Wed, 14 Mar 2018 12:08:03 +0200
 
    - by Teemu Piippo <teemu@hecknology.net> [Wed, 14 Mar 2018 12:08:03 +0200] rev 1283
 
    - added an MVC interface to the primitives tree
 
    - Sun, 11 Mar 2018 23:42:03 +0200
 
    - by Santeri Piippo [Sun, 11 Mar 2018 23:42:03 +0200] rev 1282
 
    - fixed removing objects causing some other objects to disappear
 
    - Sun, 11 Mar 2018 16:13:32 +0200
 
    - by Santeri Piippo [Sun, 11 Mar 2018 16:13:32 +0200] rev 1281
 
    - optimized triangle count
 
    - Sun, 11 Mar 2018 16:13:22 +0200
 
    - by Santeri Piippo [Sun, 11 Mar 2018 16:13:22 +0200] rev 1280
 
    - fixed: LDDocument created one removal connection to the model for each object added, so removing an object from a model of 9 objects added 9 deletion entries to history
 
    - Thu, 08 Mar 2018 11:39:18 +0200
 
    - by Santeri Piippo [Thu, 08 Mar 2018 11:39:18 +0200] rev 1279
 
    - renamed signal