Tree farm will now only chop down blocks that explicitly extend
BlockLog.  Should resolve issues of tree-farms chopping down fences/etc.
Might introduce issues to some mod-added tree-types if their logs do not
extend BlockLog.  Closes #103
add a small delay to worksite work processing if previous attempt
failed.  Should smooth tick-times with empty worksites.
update worksite base code to enable can-fit checks prior to adding to
inventory.
add some more utility methods to inventory tools
clean up need for worksite inventory overflow.  Now validate if can hold
prior to harvesting any block / picking up any item.  Will eject item
into world if canHold check is not proper for any reason.  Closes #89
Closes #102