Enable virDomainMemoryStats in the python API.  dom.memoryStats() will return a
dictionary containing the supported statistics.  A dictionary is required
because the meaining of each quantity cannot be inferred from its index in a
list.

* python/generator.py: reenable bindings for this entry point
* python/libvirt-override-api.xml python/libvirt-override.c: the
  generator can't handle this new function, add the new binding,
  and the XML description

Set up the types for the domainMemoryStats function and insert it into the
virDriver structure definition.  Because of static initializers, update
every driver and set the new field to NULL.

* include/libvirt/libvirt.h.in: new API
* src/driver.h src/*/*_driver.c src/vbox/vbox_tmpl.c: add the new
  entry to the driver structure
* python/generator.py: fix compiler errors, the actual python binding is
  implemented later

Commit 66137344feb488ea87b0d92f3c03844d9a7a7786 changed the Python detection
mechanism in configure to use AM_PATH_PYTHON. This results in a changed
install location for the Python bindings, at least on Fedora 12 64bit systems.

Before this commit libvirt.py and libvirtmod.so were installed to

  /usr/lib64/python2.6/site-packages

After this commit they are installed to

  /usr/lib/python2.6/site-packages

Mixed Python packages (containing *.py and *.so files) should be installed to
the pyexecdir directory detected by AM_PATH_PYTHON.

This restores the install location from before the AM_PATH_PYTHON commit.

* configure.in: remove unnecessary pythondir export
* python/Makefile.am: switch from pythondir to pyexecdir

Using AM_PATH_PYTHON solves the site-packages directory problem. At least
in Ubuntu with Python 2.6 and later site-packages is renamed to dist-packages
and site-packages is not part of sys.path anymore. So installing the libvirt
Python bindings to site-packages renders them unusable, because they can be
imported from there without manually including site-packages into sys.path.

AM_PATH_PYTHON detects the correct site-packages/dist-packages directory.

python-config --includes gives the correct include path for the Python header
files. The old probing code stays there as fallback mechanism.

* configure.in: use AM_PATH_PYTHON and python-config
* python/Makefile.am: remove -I because PYTHON_INCLUDES contains it now

* libvirt-override.c: Add many missing calls to allow threading
  when entering C code, otherwise python blocks & then deadlocks
  when we have an async event to dispatch back into python code.
  Fix return value check for virDomainPinVcpu binding.

* python/generator.py python/libvirt-override-api.xml
  python/libvirt-override.c: implement the bindings for
  virConnectListInterfaces() and virConnectListDefinedInterfaces()

There is currently no way to determine the libvirt version of a remote
libvirtd we are connected to. This is a useful piece of data to enable
feature detection.

suggested by danpb on irc, patch by danken fixed for proper C syntax

* python/libvirt-override.c: on event callback release the python
  interpreter lock and take it again when coming back so that the
  callback can reinvoke libvirt.

In the generated bindings, custom classes are squashed against the following
class, which hurts readability.

A mistake in the generator was causing virInterface methods to be generated
with unpredicatable names ('ceUndefine', instead of just 'undefine'). This
fixes the method names to match existing convention.

Does anyone care if we are breaking API compat? My guess is that no one is
using the python interface bindings yet.

Signed-off-by: Cole Robinson <crobinso@redhat.com>