Blender Git Loki

changes to icon loading
- look for icons in datafiles/icons (was looking in datafiles)
- was loading all images in datafiles/ on startup to check if they were the correct icon size, commented this since its unnecessary disk overhead on startup & images are checked for correctness when used anyway.
when running blender from the source dir would load splash.png every time.

also add missing NULL pointer check if the icon couldn't be loaded and ensure no buffer overflow check on icon path creation.