v1.8.2

This release provides some security updates.

• core: Fix memory leak problems(#67, CVE-2018-14072, CVE-2018-14073), thanks to @fCorleone.
  f94bc6f
  84ed0bc

• core: Fix some heap buffer-overflow problems(#68, #69, #70, #71), thanks to @fgeek.
  6a19d99
  0d70e04
  438188c
  ba21bb9

• man: Fix a typo (#66), thanks to @tsutsui.
  cf47281