Create a new tab for splitting a requirement
Add a requirement-splitting tab in the single-requirement edit panel
Create a request observer module and a controller module for splitting a requirement
Add the basic functionality of splitting a requirement and improve its request observer and controller
Add a "split requirement" button in the RequirementsPanel, rather than having a new tab
Shows statuses for splitting a requirement
Enable the split button only when legal to be clicked
Rename a function name in RequirementsPanel from "setStatus" to "setStatusMessage" to distinguish it from model.setStatus()
Merge branch 'dev-feature-split-requirement' into dev