Improve dependencies lookup process.
Improve dependencies lookup process.

Details:

1. Support cyclic references in .d.ts files.
2. Correct file resolving in case when file extension is omitted.
3. Correct handling of internal imports e.g. `import lib = mod.lib`.

rtorr/typescript-loader,rtorr/typescript-loader,andreypopp/typescript-loader,rtorr/typescript-loader,andreypopp/typescript-loader,andreypopp/typescript-loader