Test enhancement

[peter279k]

Changed log

• Add more tests
• Sperate the classes. One class is mapped a PHP file.
• Integrate the coveralls service and it's a code coverage service.
• Add the required PHP extensions checking when Composer do the package installation.
• Add autoload-dev to generate the test autoload files.
• Modify the addFilter method because the imagefilter function needs the two arguments.
• Implement the imageFlip method in ImageResize class.
  It's for the PHP version is lower than 5.5.
• Drop PHP 5.3 and set required PHP version is 5.4+ in composer.json.

Here is Travis build and the code coverage report by coveralls.

[adityapatadia]

Thanks for an amazing update. I really appreciate your work.
Can you add following things as well which will help me directly merge this in master.

1. Update the readme file for imageFlip
2. Add coveralls test badge to readme

It would be also good if you can remove the editorconfig file.

[peter279k]

Hi @adityapatadia, thank you for your reply.
The imageFlip usage I have added in README.md.
And the .editorconfig has been removed.
BTW, the coveralls test badge I think it needs to be added on your own because the coveralls badge link is point at my forked repo.

Thanks.