Fix build warning.

Merge branch 'develop'

Fix version number.

Fix version number.

Merge branch 'develop'

Merge branch 'develop'

Don't build numpy if there's no python version to target.

Merge branch 'develop'

Merge pull request boostorg#43 from Flast/patch-1

Fix a compile error with obsoleted details.

Merge pull request boostorg#49 from fatso83/develop

Add cygwin64 support to wrap_python.hpp