v0.7.0

• Add example (port of MyReadXMP app) (#82)
• Add XmpMeta::struct_field (#107)
• Add XmpMeta::contains_struct_field (#106)
• Add XmpMeta::compose_struct_field_path (#105)
• Fix memory leaks when returning strings from C++ to Rust (#104)
• Implement Display for XmpDateTime (#103)
• Add XmpMeta::localized_text accessor (#99)
• Refactor XmpMeta documentation for property accessors (#98)
• (MINOR) Rename XmpMeta::does_property_exist to XmpMeta::contains_property (#97)
• (MINOR) Rename XmpMeta.array_property to .property_array (#96)
• Add typed property setters (#95)
• Add typed property getters (#94)
• Remove Eq trait bound on XmpValue<T> (#93)