Merge pull request #1 from iljabauer/master

Refactored code for better testability
- added exceptions for status HTTP Status Codes
Update README.md
Merge branch 'master' of github.com:fhanspach/thmbnlr
- added media folder
- added two logo files
Added simple test setup
Added mock for example.com domain which will serve static data from folder
Added test for request without url
Added test for request with url but without parameters