Added ui plugin
Added UI plugin to feature. (also removed explicit version reference,
not necessary since they are filled in when building the feature)
Added src-lang code.
Moved non-debug UI launch code to UI plugin.
Added new Lang UI code, particularly for managing UI plugin images.
Fix for activating debug plugin from current UI plugin
Added launch src-lang code. Minor change to GoLaunchConfigurationTab.
Indentation normalized.
Rewrite of Go launch tabs using Lang code, fixed some related launch tab
bugs, and added some minor functionality.