sqleet v0.30.0

sqleet as a drop-in replacement for the SQLite3 amalgamation.

What's new in v0.30.0?

• SQLite v3.30.0
• rekey() now accepts a NULL key for decrypting the database
  • Previously a 0-length non-NULL key was expected
  • Thanks @johnfound for reporting the issue
• Improved support for multi-threaded concurrency
  • Handle SQLITE_BUSY from sqlite3PagerSharedClock() (7dc8126)
    • sqlite3_busy_timeout() and sqlite3_busy_handler() supported by sqleet
  • Concurrent usage of shared pager cache (disabled by default) is still buggy (#31)
  • Thanks to @rocketcyberdev for reporting the issue and testing fixes
• Minor crypto optimizations