Fixed issue #137: Php::Object("MyClass") crashed when no __construct() function was defined in it
fixed issue 107, casting a value to a std::map was not working correctly
commit d0ee242b3a617fa8676e56388ce01a8a676bf7d1 closes #107
Removed move constructor from Object class, because it caused failures when instantiating with a std::string parameter, Php::Object constructors now always first call the base constructor, and the __construct() function is now always called
fixed value destructor, reference variables should not be unreferenced
Value::refcount() is now const, and fixed a memory leak in return values