New LAC Version 5.67 uploaded late Feb 2018

Major improvements from late February 2018 (Version 5.67) include:

• Better aircraft and airfield graphics: A new subfolder, named "Optional3dModels", contains more detailed .3ds models for some of the aircraft, and for the HQ airfields. Use of these files is optional. When none of these files are used, the visual appearance of the aircraft and arfields is optimized for maximum frame-rate, which will work best on older, or lower-powered LINUX desktop PCs, and which will always result in the smoothest graphics. On the other hand, users with sufficiently modern and/or sufficiently powerful Linux desktop PC hardware can replace any of the files in the old ~/models subfolder with the corresponding files from this new "Optional3dModels" subfolder, and the corresponding aircraft or airfield will thereafter look a lot better.
• Source code has been cleaned up a little bit more. For example, I eliminated every reference to the unused "<stdlib.h>" header file. I also made the code more robust so that it is no longer possible to use misconfigured text fields within the LacConfig.txt or LacControls.txt files to cause "buffer overflow" errors. This was done by modernizing all of the relevant instances of "strcpy()" and "strcat()" within all of the code files, replacing them with "strncpy()" and "strncat()" as appropriate.
• I fixed a small visual anomaly that was causing a tiny "shimmering" effect along coastlines when flying certain aircraft. This has made visual effects even smoother when flying those planes.
• Two obscure name references were changed from "AIR COMBAT FOR LINUX" to "LINUX AIR COMBAT".
• I eliminated the redundant menu option that was allowing players to try to change their aircraft immediately before launching each mission. (The preferred way to do this is to use the prominent "DEFAULT AIRCRAFT" menu logic that is displayed at top of the list of missions.)