Archery tweaks for smoother growth

Adjusts the skills and level required for the small game and fire hardened
wood fletched arrows so they can be crafted without needing the archery
skill.

Adjusts the dispersion of the longbow and the selfbow in order to get over
the max dispersion learning curve. The longbow can get you to 5/5
marksman/archery and the selfbow can get you to 2/2 marksman/archery.

Adds an alternative method of getting fletchings. By taking taking some
bones and water and boiling them down at a fire, you can make bone glue.
You can then use the bone glue as a varnish or hardening substance on rags
and leather in order to make fletchings.

Most arrows are now able to disassembled. As a balance point, a binding
component has been added that is unrecoverable. You can use superglue,
bone glue, or thread-like items as the binding component.

Added heavy field point arrow and heavy fire hardened arrow intermediate
items in order to accomidate the new disassembly change.
Reverted this and set the recurve to 120 based on IRC discussion.  Will need another rebalancing at a later date, but bows that claim to sacrifice accuracy for power should not be the most accurate ones in the game.