* Added functions and statements
  * Added sqrt() function
  * Added round(), ceil() and floor() functions
  * Added lookup() function for linear interpolation in value list
  * Added projection(cut = true/false) statement
  * Added child() statement for accessing child nodes of module instances
  * Added mirror() statement
* Improved DXF import code (more entities and some bugs fixed)
* Added feature for dumping animation as PNG files
* Added a preferences dialog
* Now using CGAL's delaunay tesselator
* Now using eigen2 for linear algebra
* Reorganisation of the source tree
* Some bugs fixed, maybe some new bugs added
