Handle property visibility and __get, refs #79

Protected and private properties should not be available
to JS context.  Instead call __get function, if the
property is not accessible.
Don't allow JS to overwrite protected/private properties
Call __set if JS accesses private/protected property
Add test on visibility of properties on enumeration
Initialize fci.no_separation correctly
Call INIT_ZVAL on stack-allocated zval
Don't unset non-public properties, just hide them.

Before non-public properties were not reset also, trying to
unset them just caused a fatal php error, effectively crashing
the whole script.
Add test on property visibility regarding hasOwnProperty
Merge pull request #90 from stesie/fix-property-visibility

Fix visibility of PHP properties in JS