Inventory Pickup Commit.  Character can now pickup objects by mousing over
and hitting a specified key 'e' by default.
Add weight carry weight to character item weight/volume to InventoryItem
and changed PC pickup function to check character current carry weight
with max carry weight before performing pickup.
Added the Inventory UI.
Getting rid of some files added accidentally
Commit before I start working on the UI Mouse Input and break it
Added the click widget and got it working mostly.  Also added a currently
empty "HUDWidget" which will be used to draw the actual gameplay HUD
Pickup and Drop are Now Functional
The pickup and dropping of items now works from the Inventory screen.  I
am concerned at the sheer number of callbacks inside the Slate code right
now.  Every one of those callbacks is called every frame.  I'm not sure
what kind of an impact this is having on performance yet though.  Video
will be going up later today.
Transitional: Do not merge from
Just a transitional commit to save progress while I work.

Currently I've converted the UI for the inventory and popup to respond
to keyboard commands.  I haven't finished linking the popup menu with
the actual commands it needs to execute.  Also, in this commit is the
HealthItem class which extends from InventoryItem.

The Slots for both the inventory grid and popup menu are now separate
custom widget classes.  I had to do this to override the OnKeyDown
method within each.  They are named The_Shell_InventorySlotWidget and
The_Shell_PopupButtonWidget respectively.  I will likely be doing the
same for the Info Box widget as well, though that depends
on what I will have to have it do.  Separating these out has the
advantage of allowing for deeper tracking of the items in the slots.
Got the bugs worked out, just need to clean up
Final commit before merge