JavaScript LS scaffolding + JS module inference

[RyanCavanaugh]

This is a subset of the prior PR that carves out only the code we need to get a) JavaScript intellisense in general and b) CommonJS module inference in JavaScript files.

Includes work by @vladima in 'services' to get the correct compilation context to Roslyn

[DanielRosenwasser]

Consider extracting this out into a function.

function shouldRecordAmdDefineName(index: number, moduleName: string) {
    // record first item in the list only if its name is not "require"
    // record second item in the list only if its name is not "exports"
    // record third item in the list only if its name is not "module"
    // record all other items in the list unconditionally
    switch (index) {
        case 0:
            return moduleName !== "require";
        case 1:
            return moduleName !== "exports";
    }
    return index !== 2 || moduleName !== "module";
}

[RyanCavanaugh]

We can remove the AMD logic entirely

[ahejlsberg]

Don't think you need the declaration.parent.kind test. There should never be a case where that isn't true.

[ahejlsberg]

We usually put a blank on both sides of the | operator.

[RyanCavanaugh]

@vladima can you address the comments in program.ts?