added different types of files and image helpers for testing
made specs to check other types of files are accepted on cdn communication system
communication system upload working with extension
added tests for different file extensions for download
added file extension to rename, delete and info
make sure the generator adds the file_extension
Merge pull request #21 from BenjaminMedia/features/different_image_formats/communication_system_settings

Features/different image formats/communication system settings
added file_extension to the database in the dummy app
added file_extenion to the concern and tests to it
Merge pull request #23 from BenjaminMedia/features/different_image_formats/image_concern

Features/different image formats/image concern
changed source_file_path to source_file
added check for the file content type
added white list mechanism
fixed white list extension and added tests
Merge pull request #24 from BenjaminMedia/features/different_image_formats/image_format_checker

Features/different image formats/image format checker
Merge pull request #22 from BenjaminMedia/projects/different_image_formats

Projects/different image formats
added aspects and crops to the dummy app
aspect can either be a symbol or a string
url can receive width, height and aspect as argument to return the correct url
added tests database for travis to work