Construo 0.2.1

• added switch to disable thick lines in X11
• added runtime switching to fullscreen, press 'F11'
• different cursors for different tools
• added a blender like 'remove doubles', press 'j'
• fixed 'make install'
• added grid support (press 'g')
• fixes crash-bug in with user/ directory
• fixed some missing keybindings fixed
• fixed missing #ifdef/#endif for XVidMode, caused compile failure if
  Xvidmode is not present
• added zlib support for compressed construo files (.construo.gz)
• some small optimizations
• fixed problems with 16bit XServers
• more example constrution