Combat traits in Ruler Designer + minor additions

Combat traits can now again be customized in the Ruler Designer.  The
startup trait distribution event has been modified to respect a
customized (or otherwise already assigned) combat trait as well as to
take into account the agile and clubfooted traits, and the per-character
combat_skill variable is freed after use.
ChangeLog update

Combat traits are again customizable with the Ruler Designer
Merge pull request #45 from zijistark/beta

Combat traits in Ruler Designer + minor additions