Bug 2228

As per Scott's review, please update the content of the Image configuration screen as follows:

1. Change the select a machine explanatory text to: "Your selection is the profile of the target machine for which you are building the image"

2. The Layers information bubble includes a link. The link target should be: http://www.yoctoproject.org/docs/current/dev-manual/dev-manual.html#understanding-and-using-layers

3. The tooltip for the Templates button should say: "Load a previously saved template"

4. Change the "My images" button label to just "Images"

5. The tooltip for the "Images" button should say: "Open previously built images"

6. The tooltip for the "Settings" button should say: "View additional build settings"

7. Add a tooltip to the "Build packages" button. This tooltip should say: "Build recipes into packages" 

8. The tooltip for the "Build image" button should say: "Build target image"

Scott, feel free to add / amend as required.