GUI-48: Scaling Group detail pages

Implemented the following for a given scaling group …

- Added "Details" title to second section on "General" tab
- Moved termination policies to Capacity section and added help text to emphasize order matters
- Enabled instance termination in the "Instances" tab (Note: added a "decrement capacity?" boolean.  Need to confirm if this makes sense and what the default should be (on/off) if we're keeping it.)
- Display notice with link to Add Policy page if a scaling group has no policies.  The note is display on the General tab and Instance tab.
- Converted measurement inputs into a mad lib on the Create Alarm dialog.