v0.10.0 - Validating media and dynamic points

⚠️ Please go to #412 and say what PHP version you're using, since we plan to increase the minimum PHP version number to 5.6(and deprecate the 0.x branch)! ⚠️

Added:

• #394 Validating media file (FFProbe#isValid(string $pathfile))
• #407 Support crop with dynamic point (thanks @letungit90!)

Fixed:

• #419 Fix PHP 5.3 compatibility (thanks @esokullu!)

Changed:

• Various updates to the README