added data source & licensing

extract-DECC-LSOA-energy-data-from-excel.do

-* Extract data from DECC extracts
+* Extract data from DECC LSOA level domestic energy consumption data:
+* https://www.gov.uk/government/collections/mlsoa-and-llsoa-electricity-and-gas-estimates
+
+* Original data available from: UK DATA ARCHIVE: Study Number 7518 - National Energy Efficiency Data-Framework, 2014
+* http://discover.ukdataservice.ac.uk/catalogue/?sn=7518
+* Ben Anderson, Energy & Climate Change, Faculty of Engineering & Environment, University of Southampton
+* b.anderson@soton.ac.uk
+* (c) University of Southampton
+* Unless there is a different license file in the folder in which this script is found, the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license applies
+* http://creativecommons.org/licenses/by-nc/4.0/
 
 clear all