Q:

How to make a square grid for UV maps

Since the shape is organic and not a pure cylinder every method I attempt when trying to make a UV map of a sleeve of a T-shirt I cannot get a square grid in the UV editor.  This is the closest I got to having a grid.  Ctrl+V just makes a mess.  Besides editing every single point I have no idea how to achieve this.  Pictured is half the sleeve mapped. 
---UPDATE---
The suggestion of Follow active quads gives me a skewed diagonal irregular large on top smaller at the bottom grid.  
New information, new problem:
It was suggested to use  the The UVSquares addon in the possible duplicate entry.  I followed the UV squares addon tutorial, I didn't have an entry for "3D view: Screencast keys" so I found it and install it from file and activated it.  Done!  But I do not have the "Mesh: UVSquares" entry to activate once I installed from file the uv_squares.py
What can I check to get it to work?  

A:

Follow Active Quads will work in this case, but you need to pay attention to a few things to get a clean 90-degree unwrap. 
In this method Blender takes the active face and lays out other selected faces around it, following its shape in UV space (not in 3D space).  In other words, it is important how your active quad looks in the UV space. 
If your mesh doesn't have a UV map (you didn't unwrap it), the active face is mapped to the size of UV space (a perfect square/rectangle) and other faces are placed around it accordingly. 
But if your mesh already has a UV map, the active face is not mapped to the size of UV space, but rather its existing shape in UV space is used. 
For example, if your UV map looks like this (notice the shape of the active quad):

the result of unwrapping with Follow Active Quads will look like this (notice how selected faces are following the shape of the active face):

To get a nice grid, you have to turn your active quad into a perfect rectangle in UV space.  You can do that by editing the vertices manually, by resetting the UV map (U > Reset), or by using Lightmap Pack unwrap (U > Lightmap Pack > OK).  I usually use Lightmap Pack unwrap in cases like this.  It's fast and it fits all the faces into UV space (they are smaller, so after using Follow Active Quads the unwrapped grid isn't huge). 
The result of using Lightmap Pack will look like this (notice the active face turned into a perfect rectangle). 

Now it's OK to use Follow Active Quads - you should have a nice 90-degree grid:

To sum it up, here's your workflow:

Select all faces you want to unwrap. 
Use Lightmap Pack unwrap (U > Lightmap Pack > OK). 
With active quad selected use Follow Active Quads (U > Follow Active Quads). 

A:

Have you tried 'follow active quads'?  It is a built in Blender tool.  Basically, select a bunch of faces and find the tool in the unwrap menu:

You can see that one quad, the one directly under the menu, is shaded differently.  It is the active quad in this case.  With this method it has a special meaning, this quad will be put into the 0 - 1 range of the UV editor, the other faces will be placed accordingly (as long as there is no pinning).  So after unwrap, you'll need to zoom out a LOT to see the UV map, and then scale it back down. 