Vmware Client SDK plugin

https://gist.github.com/712934

I'm not sure the process to get this merged in, but I figured it would
be useful to some people.

This is against collectd-4.7.4, so it may be a little stale as well.

Let me know what's needed to get this merged officially upstream and
I'll be happy to work on it in my spare time.

Thanks!
VMware Plugin: Various improvements.

Made all changes requested by Florian Forster

- Removed trailing white spaces in configure.in, src/collectd.conf.pod, src/vmware.c
- Removed unused plugin_vmware variable from configure.in
- Removed unneeded include statements for stdarg.h, stdio.h, dlfcn.h
- Changed include for vmGuestLib.h to use angle brackets instead of double quotes
- Changed global variable VMGuestLibHandle to static
- Changed printf errors to use ERROR() macro
- Changed variable names to follow the normal C / collectd naming schema, e.g. "elapsed_ms" and "cpu_used_ms".

Rebased on top of Edward Muller's commit. --octo