ChainTipper Release 1.0-beta19

1.0-beta19:

• parse claimed/returned tx id, include in data and add "open blockexplorer to claimed/returned tx" menuitem
• Tip amount_text now set to instead of taken verbatim from message. Fixes: tip amount text newlines screw up gui (reported by remora around 10.9.2021).
• auto-import from reddit on startup (starting at max(date) of stored tips)
• new functionality to export tip list to csv or json file (in tip context menu)