Added more info to the README to reflect our recent data upgrade experiences.
Minor fixes to README updates.
Minor fixes to README updates: whitespace edition.
Added command to delete cached HSIA files from TileCache directory.
Added note about -128 nodata value to README.
Added a note about chown'ing the TileCache files to README.
Added more information about PostGIS import step to README.
Made part about NoData value more clear in README.
Merge branch 'readme_data_update'
Merged README and Data Sources changes.