Added tag v18.8 for changeset a6c2b16111b8
Created release v18.8
Fixed a warning about signed/unsigned comparisons.
updated docs
Fixed a minor interface usability flaw in the scan_fhog_pyramid.  It wasn't
documented that you couldn't change the padding, cell size, or window size
parameters between calls to load() and detect().
The new serialization API that works like serialize("filename") << object; wasn't
opening files in binary mode.  Oops.  This is now fixed.
updated docs