Log Message:
Update to 1.8.6:

NEW IN WAF 1.8.6
----------------
* Python file installation fixes
* Fix for classes containing utf-8 names
* Hide the progress bar when running waf -ppp
* Support more header extensions in subst/is_copy
* Handle non-string and non-list values in substitutions (subst)
* Show how to track build files timestamps to force partial rebuilds \ 
(build_file_tracker.py)
* Added a new extension to detect blender libraries
* Added extras/prefork.py, extras/preforkunix.py and extras/preforkjava.py
* Updated demos/d
* Updated demos/vala
* Updated playground/protobuf
* Updated playground/cython
* Updated playground/dynamic_headers
* Updated playground/netcache
* Qt5 detection improvements