Merge pull request #29 from mobli/master

Added constants to interfaces
Fixing warning reading class constants [ci skip]
Fixing coding style [ci skip]
Requiring CommandAbstract and CommandInterface [ci skip]
Merge pull request #32 from mobli/master

Fix return macros to work with expressions
Changing zephir_array_update by zephir_array_update_zval [ci skip]
Ternary operator support at syntax level [ci skip]
Fixed arithmetic expressions, support to simple %= operation [ci skip]
Fix memory bug - Added empty array as default param

- Fix a critical memory management bug that occurs when returning a
member from a method that needed local variables, because
ZEPHIR_MM_GROW() was called but ZEPHIR_MM_RESTORE() was not.
- Added empty array as possible default parameter to methods. For
instance:
public function mymethod(myParam = [])
- Added getParameter($name) to CommandInterface