OTHER: Move more code into cli_infos from main.
OTHER: Split cli build into objects and executable.

The reason for this is to make it possible to write unittests
by simply adding 'use = xmmscli' to the test suite.
OTHER: Add a unittest for command_trie.
OTHER: Tweak valgrind flags for test execution.

Adds --num-callers=20 to catch more recursively deep problems, and
fills used/unused memory with easy to spot constants that may help
find memory corruptions.
OTHER: Fix leak in command_trie lookup.