Hello, sciter added API

[xizhengchao]

UINT SCFN(SciterElementUnwrap)(const VALUE* pval, HELEMENT* ppElement);
UINT SCFN(SciterElementWrap)(VALUE* pval, HELEMENT pElement);

UINT SCFN(SciterNodeUnwrap)(const VALUE* pval, HNODE* ppNode);
UINT SCFN(SciterNodeWrap)(VALUE* pval, HNODE pNode);