grunt-spritesmith and load-grunt-config doesn't work

Question

When I run task:

grunt sprite

I receive this error:

jit-grunt: Plugin for the "sprite" task not found. If you have installed the plugin already, please setting the static mapping. See https://github.com/shootaroo/jit-grunt#static-mappings

Warning: Task "sprite" failed. Use --force to continue.

Aborted due to warnings.

Grunfile.js & --config-debug here: https://gist.github.com/JosephWM/c43530246cc0ba5d060a

All tasks works fine, but I cannot run grunt-spritesmith. Please help.

update: problem solved. U can see code of changed files here (link in comment)