Add incomplete draft of duk_prop_ownpropkeys.c
Add incomplete draft of duk_prop_ownpropkeys.c

svaarala/duktape,svaarala/duktape,svaarala/duktape,svaarala/duktape,svaarala/duktape,svaarala/duktape,svaarala/duktape,svaarala/duktape,svaarala/duktape