Support more tsconfig.json scenarios

[brphelps]

Right now, the tsconfig.json reader is somewhat limited -- it's only looking for "files" sections and doesn't take into account other significant parameters like "exclude" and "compilerOptions.rootDir".

Since these are critical to being able to process a tsconfig.json the same way a TypeScript compiler would, support should be added.

[aciccarello]

I took a look at the status of Typescript 2.0 support. As a workaround, several options were temporarily ignored via #308 to allow builds to continue but people using the new features may not be able to compile. See #234 for the original discussion.

feature	issues	PRs	status
baseUrl	#340	#342	Merged
paths	#340	#342	Merged
include	#326	#359	Merged
lib	#315		Ignored
types	#311		Ignored
typeRoots	#305		Closed
rootDirs	#386		Open
extends	#380		Open

[Gerrit0]

As far as I know - 0.20 respects all compiler options and behaves the same as tsc does.