changed self to TimberImageLibrary instead of action hook
added link to TidyRepo
Merge branch 'master' into 230_image_library

* master:
  removed "public" keyword -- methods in question are public by default
  fixes #230
  adding test for short codes close #125
  added source to composer.json as recommend by @rarst in #50
  test for autoload file before inclusion from composer ref #50
  changed Twig requirement to ~1.15