Base for CLI tool profiling

This patch implements a simple wrapper for
profiling different CLI commands and saving
the results.

cProfile is used as a profiling tool; results
are saved in both prof and DOT-graph formats.

In order to enable profiling NAILGUN_LOAD_TEST
variable should be set.

Change-Id: Ia9f6d19960fbe35e034fa85bf6303f3a419a7a75