Check File if it is an Image and save it (Write Class)

Write ImageHandler Class (see annex). The Class shall be used as described in the Situation section. Situation: ---------------- Two images are on an external server 1. check if files really are images ->isImage() 2. compare if the two images are the same ->areEqual() 3. remove all non-visual data (Exif) ->stripExif() 4. save the image ->save() Restrictions: ----------------- - As one can see, the images are accessed in several functions. But each image shall be retrieved only once from the external server (only one HTTP-Request per image!) - attention to PSR Coding Style Guidelines would be appreciated Task fullfilled: ------------------ - all functions are working (I test that with unittests) - per image only one http request is done