Gridcoin 5.0.1.0-Leisure release

We are releasing a small maintenance leisure release to correct a few compilation problems on some platforms, and address a few corner-case issues that were already addressed on the hotfix branch, plus some other corner-case technical changes.

The most visible highlight of this release is the fixing of the display of transactions with messages prior to the hard-fork point and the new wallet backup file retention maintenance functionality.

https://github.com/gridcoin-community/Gridcoin-Research/releases/tag/5.0.1.0

[5.0.1.0] 2020-09-20, leisure

Added

• wallet, rpc: Implement backup file management functionality #1735 (@jamescowens)
• build: Add support for building with musl and Alpine Linux #1866 (@cyrossignol)
• rpc: Display local IP addresses in "getnetworkinfo" output #1884 (@cyrossignol)

Changed

• refactor: Implement std::atomic_bool OutOfSyncByAge #1877 (@jamescowens)
• net: Optimize locator construction for "getblocks" messages #1880 (@cyrossignol)
• refactor: Combine GetOrphanRoot() and WantedByOrphan() functions #1883 (@cyrossignol)
• refactor: Convert beacon and backup timers to scheduled jobs #1885 (@cyrossignol, @jamescowens)
• refactor: Rename "neural network project-wide #1886 (@cyrossignol)

Fixed

• collection of post Fern hotfixes (@jamescowens):
  • Change QDateTime::toSecsSinceEpoch() to QDateTime::toMSecsSinceEpoch()
  • Change QDateTime::fromSecsSinceEpoch() to QDateTime::fromMSecsSinceEpoch()
  • Ensure boost placeholders are compatible
  • Fix subtle bug in GetEstimatedStakingFrequency
• test, ci: xenial support #1867 (@div72)
• lib: Fix compatibility with Boost 1.74 #1869 (@theMarix)
• test: Fix tests for _GLIBCXX_ASSERTIONS #1870 (@cyrossignol)
• util: fix Windows API for default data directory with wide characters #1871 (@cyrossignol)
• gui: Fix OP_RETURN filter to avoid hiding transactions with messages #1873 (@cyrossignol)
• net: Fix stalled blockchain progression #1876 (@cyrossignol)
• superblock: Fix regression for superblock builder optimization #1881 (@cyrossignol)
• util: Fix scheduler crash after waking from sleep #1888 (@cyrossignol)