2.1.2

Major fixes:

• Fix leak of database space that could occur when calling restore_savepoint()
• Fix leak of database space when calling delete_multimap_table()
• Fix database corruption which could occur when restoring a savepoint. This edge case is rare,
  and could only occur if the database was less than approximately 4TiB when the savepoint was
  created, and greater than 4TiB when the savepoint was restored
• Fix edge case where a transient I/O error that occurred during transaction commit, but then did
  not reoccur when the Database was dropped, could cause database corruption

Important: If your application has called restore_savepoint(), delete_multimap_table(),
or you suspect it may have experienced a transient I/O error during transaction commit.
It is recommended that you run check_integrity() after upgrading to this version.
This will both detect corruption and clean up any leaked space.

Other changes and fixes:

• Optimize page freeing to reduce the size of the database file
• Fix several cases where check_integrity() would return Ok(false) instead of Ok(true)
• Fix some cases where compact() did not fully compact the database
• Make the metadata overhead returned by WriteTransaction::stats() more accurate
• Return StorageError::ValueTooLarge when a key-value pair exceeds a total of 3.75GiB.
  Previously, a panic would occur for key-value pairs that were approximately 4GiB.
• Downgrade several info! log messages to debug!
• Improve documentation