version 1.53 released

Five more groups are processed for SYNOP sections 3 and 9. The summary also shows the direction for wind gusts and the offset to the exact observation time. If a DB is used as message source, station information is also fetched from this DB. In the UIs, SYNOP stations are now distinguished by station type instead of source. The GUI demo now works with browsers based on WebKit. The check for the exact Perl module version was improved. Style information for the UI was moved to a CSS file. The installation script was improved. Some minor bugs were fixed anda few smaller improvements were made.