The new baselines all look correct to me, but obviously a number of the
tests need to be updated to reflect union types and the new behavior of
best common type. This commit does not cover that.

The tuple type tests from master need to be updated to reflect the new
best common type behavior from union types. This commit simply accepts
the baselines as they are.

Conflicts:
	src/compiler/checker.ts

Lanugage Service support for union types

Conflicts:
	src/compiler/checker.ts
	src/compiler/types.ts
	src/services/services.ts
	tests/baselines/reference/assignmentCompatBetweenTupleAndArray.errors.txt
	tests/baselines/reference/bestCommonTypeOfTuple.types
	tests/baselines/reference/bestCommonTypeOfTuple2.types
	tests/baselines/reference/castingTuple.errors.txt
	tests/baselines/reference/contextualTypeWithTuple.errors.txt
	tests/baselines/reference/genericCallWithTupleType.errors.txt
	tests/baselines/reference/indexerWithTuple.types
	tests/baselines/reference/numericIndexerConstrainsPropertyDeclarations.errors.txt

Conflicts:
	src/compiler/types.ts
	src/services/services.ts