Remove failure block param on hnk_setImage and hnk_setBackgroundImage UIButton extension methods
Merge branch 'master' into improvement/hnk_setImage_failure_block

Conflicts:
	Haneke/UIImageView+Haneke.swift
Merge pull request #110 from Haneke/improvement/hnk_setImage_failure_block

Remove failure closure on hnk_setImage and hnk_setBackgroundImage UIButton extension methods, closes #109