id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
156	tile update	Martin Kolman	Martin Kolman	" * replace tiles by newer ones

 * timestamps
  * last modified time for files
  * timestamp for tiles in database
  * last modified in http headers

 * automatic update - download only headers and replace old tiles automatically

 * batch update - check & update all currently stored tiles
"	enhancement	new	major		gps				mcepl@…