Additional error handling for copy_file (wallet backup), copied from Bitcoin source
Reduce sync frequency for blkindex.dat

https://github.com/bitcoin/bitcoin/pull/1114

Will hopefully result in better performance especially for disk based hard drives.
GUI improvements and fixes (version 0.3.64)
- Configure name: added template for DNS/IP to avoid entering JSON manually (custom JSON still possible - with simple validator).
- Fixed the case when automatic firstupdates could still consume additional coins and send them back as change (SelectCoins(0) always selects at least one tx-out)
- Fixed conflict of -mininput and -rescan (rescan ignored mininput, thus missing transactions lower than the default mininput)
- Fixed display of amounts for name_* transactions. BUGBUG: some people still report discrepancy between "getbalance" and "getbalance *"
- Added waiting for full sync before sending automatic firstupdates
Merged Bitcoin commit c40a5aaaf484855a4350fd702e8e72fd21a68155
Truncate oversize 'tx' messages before relaying/storing.

Fixes a memory exhaustion attack on low-memory peers.
Workaround for exit crash