(defendant seller appealed trial court order to complete exchange of land with plaintiff buyer; buyer approached seller proposing land trade to satisfy setback requirements of local zoning ordinance; parties shook hands and buyer proceeded with construction plans; thereafter, seller threatened to demolish building for failure to pay more than amount which parties originally agreed; buyer sought specific performance of contract; seller claimed statute of frauds precluded enforcement of oral agreement and agreement too indefinite for enforcement; appellate court held that buyer occupied parcel and undertook expense of construction in reliance upon agreement; doctrine of part performance applied as exception to statute of frauds; ordered parties to perform on oral agreement).