fix number-input widget saving text / validating text on every text
input instead of just when enter pressed.  Closes #53
fix work-order item saving time-entry data.  Closes #48
fix NPE on render of worksite work-bounds.  Closes #47
implement inventory methods on mailbox tile
fix worksites, torque blocks, mailbox, and warehouse blocks to drop
inventory when broken.  Closes #50