[C] Correct alignment when dissection add counter commands in aeron_driver_agent.c.  Use memcpy for lengths to mimic code style used when decoding commands in conductor.
[C] Correct alignment when dissection add counter commands in aeron_driver_agent.c.  Use memcpy for lengths to mimic code style used when decoding commands in conductor.

EvilMcJerkface/Aeron,real-logic/Aeron,mikeb01/Aeron,EvilMcJerkface/Aeron,real-logic/Aeron,mikeb01/Aeron,mikeb01/Aeron,mikeb01/Aeron,real-logic/Aeron,EvilMcJerkface/Aeron,real-logic/Aeron,EvilMcJerkface/Aeron