openbox: new package

openbox: new package

Add support for the Openbox Windows Manager.

[Thomas:
  - don't mention MMU in the Config.in comment.
  - wchar was forgotten in the Config.in comment.
  - the dependency of the comment on thread should be "depends on
    !BR2_TOOLCHAIN_HAS_THREADS" so that the comment is shown when
    thread support is *not* available.
  - add missing select of BR2_PACKAGE_XLIB_LIBXFT and
    BR2_PACKAGE_XLIB_LIBXRENDER which are needed for pango to have xft
    support, otherwise the build fails with "configure: error: Package
    requirements (pango >= 1.8.0 pangoxft >= 1.8.0) were not met:"
  - remove useless empty newline in the hash file
  - add missing dependency on host-pkgconf, which is needed since
    the configure.ac uses PKG_CHECK_MODULES.]

Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>