Included memory usage per VM

Included all the metrics about the actual memory used by VMs (as
returned by libvirt.virDomainMemoryStats)
build: remove obsolete reference to bundled libiptc

Libiptc was removed 3 years ago in 99364c70, so this option to
./configure isn't of any use anymore.
build system: correct warning about 'INCLUDES'

This suppresses this warning when running build.sh:

Makefile.am:5: warning: 'INCLUDES' is the old name for 'AM_CPPFLAGS' (or '*_CPPFLAGS')
build system: correct warning about subdir-objects

This suppresses this category of warnings when running build.sh:

src/Makefile.am:NNN: warning: source file 'XXX' is in a subdirectory,
src/Makefile.am:NNN: but option 'subdir-objects' is disabled
enable logging for older versions of librdkafka
Fixed memory leaks

Fixed memory leaks
README: cleanup & consistency

 * add 2 plugins missing from plugin list
 * add 2 libraries missing from prerequisites section
 * remove reference to bundled libiptc
 * add a few missing references to plugins in the prerequisites section
 * consistent quoting of plugin names
 * wrap lines at column 80
Merge pull request #688 from mfournier/misc-build-cleanups

Misc build cleanups
Merge pull request #312 from jazzmes/libvirt-mem-usage

Included memory usage per VM
ignore tests output
add a conditional for the new dbi reentrant driver interface
add write_kafka to example config