Support symbol kind for union properties
add test for quick info
Add support for union properties in goto def
Support find all refs on union properties
Use getRootSymbols for all union property needs
Merge branch 'unionTypes' into unionTypesLS

Conflicts:
	src/compiler/checker.ts
	src/services/services.ts
Fix contextually typed object literal proeprties that are not properties of the union type but are properties on of one of its constituant types
respond to code review remarks
ensure unionProperty symbols have declarations set at creation time
Handle union properties completions on apparant types
Add a temporary fix to quick info
Merge branch 'unionTypes' into unionTypesLS

Conflicts:
	src/compiler/checker.ts
Merge pull request #861 from Microsoft/unionTypesLS

Lanugage Service support for union types