2.1.4

• Optimize first() and last() to be almost 2x faster
• Improve in-memory cache algorithm to resolve edge cases where certain pages could become
  uncacheable under cache pressure
• Fix bug in read cache where the read cache could become disabled. This was likely to occur in
  multithreaded workloads when the read cache was smaller than the database file. This bug lead to
  5-10x performance degradations for some workloads