Benchmark for parsing big XML documents.
Basic memory profiling setup.

This makes it a bit easier to profile memory usage of certain components and
plot them using Gnuplot. In the past I would write one-off scripts for this and
throw them away, only to figure out I needed them again later on.

Profiling samples are written to profile/samples and can be plotted using
corresponding Gnuplot scripts found in profile/plot. The latter requires
Gnuplot to be installed.