Removed mention of 3 separate blocks for header region. We'll now be using system regions that have UI button left/right features.
Forms now render an '*' next to required field labels.
Added system_regions_list(). Adjusted drupalgap_theme_load() to expect drupalgap.theme.regions to be keyed by the region name, it then sets the name variable on the region JSON dynamically so theme implementers don't have to. Converted the easystreet3 app theme's regions to match this. Adjusted drupalgap_theme_load() to make sure the loaded theme has the system regions specified, throws a console warning if the theme doesn't have the region(s). Added UPGRADE.txt.