64-bit warning fixes
Update to newer OSX version/XCode
Add delete button image
Add (hidden) delete button in section header view (not yet hooked up)
Added outlets for add job and delete employee buttons
Remove unused property
Ensure UI updates happen on main thread
Allow employees to be deleted: resolved hughescr/Timesheets#8
Make work code and location more generic, fixes hughescr/Timesheets#10
Do not need to force table reloads after deleting rows/sections