Adds :back: , :black_medium_small_square: , :black_small_square: , :package: , :sparkle: , :white_black_square: , :white_medium_small_square

Adds :back: , :black_medium_small_square: , :black_small_square: ,
:package: , :sparkle: , :white_black_square: ,
:white_medium_small_square: , :white_medium_square: ,
:white_small_square:
Adds :black_medium_square: and :white_medium_square:

Adds :black_medium_square: and :white_medium_square:
Removes duplicate "white_black_square" image from images folder

Removes duplicate "white_black_square" image from images folder
Merge pull request #180 from dlambl/master

Changes for issue #170