Include namespace Smartcoin for all classes.
Change autoload to psr-4 pattern.
Merge branch 'feature/Include_namespace_for_all_class_and_fix_autoload' into develop
Create the method save to Charge. It allow change charge's description.
Remove PHP 5.2 and 5.3. Also remove hhvm
Smartcoin PHP library version 0.2.0
Merge branch 'release/0.2.0'