Bartelome enables Converts to be FreeColonists

[HighwayofLife]

• Currently in FreeCol (and Col1), Bartelome joining congress causes native converts to be converted to Free Colonists. The effect is one-time.
• This change allows Native Converts to become Free Colonists by being "cleared" from the "clear specialty" menu option.
• This change also allows Native Converts to be educated in the outdoor skills that they are skilled at in half the time it would take a Free Colonist to be educated with that skill.

• Adds the ability for Free Colonists to gain experience when producing goods indoors and become experts.
• Percentage (probability) is based upon the skill level of the position.
  • Carpenter is skill level 1, so has up to a 4% chance
  • Statesmen and Preacher are skill level 3, so have up to a 2% chance
  • All other occupations are skill level 2 and thus carry up to a 3% chance
• The current default behavior of FreeCol is that outdoor activities all carry up to a 4% chance, regardless of skill level.