Log Message:
waf: updated to 2.0.15

NEW IN WAF 2.0.15
-----------------
* Fix Python path detection under Git-Bash
* Provide an option to disable args files
* Improve command line length calculation for args files
* Add libs/stubs to Cuda library path
* Suppress ant_glob java warnings
* Support multiple 'default_cmd'
* Warn when buildcopy is used without any files to copy
* Protobuf examples enhancements
* Fix all DeprecationWarning: invalid escape sequence