Removed incorrect iCCP chunks from GUI resources.

Also removed malformed tEXt chunk from a logo PNG.
Added interlace handling to PNG decoder.

libpng 1.5+ recommends a call to png_set_interlace_handling() if you use
png_read_update_info and png_read_image. It will generate a warning
without it.
Merge pull request #1371 from HapeMask:fix-png-warnings