libgpgme: improve language bindings

libgpgme: improve language bindings

The C++ bindings require C++11 support with minimum gcc version 4.8, so
handle it accordingly.

The new python bindings require some work, but since they were
previously unavailable just disable them for now until someone is
interested in building/using them. Fixes:
http://autobuild.buildroot.net/results/685/6853c21aa084952bc232f0ec3e96dcb972d8fbfe/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>