Add libevent-2.0.22-stable code

Existing NOTICE and MODULE_LICENSE_BSD_LIKE files describe this code.
Removed the following directories to reduce size:
  WIN32-Code/*
  compat/*
  m4/*
  sample/*
  test/*

Bug: 22229743
Change-Id: I1f32e0e7467edaa3c5ea5991b5bbec2db50762ff
110 files changed