MAINTAINER AVATAR

"OF_MAINTAINER_AVATAR" [NEW]
 - Full path to maintainer's avatar that will be shown on about page
 - Image should be 32 bit (!) PNG, 192x192 px
 - Size of image should be as small as possible (~50kb), use "advdef -4z xxx.png" to shrink image
 - Don't put NSFW content to avatar
 - Not recommended if you building for phone with small recovery partition
 - eg. 'export OF_MAINTAINER_AVATAR="/home/yillie/avatar.png"'
 - default = nothing


Signed-off-by: Samuel Kendall <kinguser981@gmail.com>