moisture driven dimensional change

Added functionality for the moisture driven dimension change calculation
Added constructor

Added constructor with all args - only makes sense for when a getWood()
or similar function is implemented in the database so it can make the
object all at once and because it's good practice to have your
properties defined or calculated when calling your constructor.
updated comments to reflect return

decided to return the change in dimension instead of the percentage
change, as that can be calculated later and this will allow for display
as a fraction.
Added empty form for dimension change
Merge pull request #1 from mcmahonn/master

dimensional change function complete