0.28.1

• Fixed: Databases with an impossible declared search tree size are now
  rejected during open/verify instead of causing runaway allocation
  during validation.
• Fixed: within() now rejects IPv6 CIDRs on IPv4-only databases instead
  of yielding unrelated networks.
• Fixed: Verification now rejects truncated scalar/string payloads instead
  of skipping past them and reporting the database as valid.
• Fixed: LookupResult::network() now uses the reader's measured IPv4
  subtree depth instead of assuming it always begins at bit 96.