Add support for "exclude" in tsconfig.json

[mhegazy]

tsconfig.json picks all files in the containing folder by default, this is problematic with "node_modules" that contain .ts/.d.ts that are not relevant to the project. "files" is not useful here because of the lack of support for globs (see #1927).

Proposal:

• support a new property "exclude" that specifies a list of directories/files to exclude.
• "exclude" is ignored if "files" is present.

{
    "compilerOptions": {
        "out": "../../built/local/tsc.js",
        "sourceMap": true
    },
    "exclude": [
        "script/helper.ts",
        "node_modules"
    ]
}

Note: This is needed if we want any of gulp/grunt/task runner/ProjectK support in VS .

[briandipalma]

Would glob support be enough not to require this feature? I've also had this issue where node_modules was being built but with glob support I'd be fine.