Do not rename imports from ambient modules

Issue explained by @bbgone in https://github.com/Microsoft/TypeScript/issues/8118#issuecomment-212218038 Renaming an import alias for a module coming from a .d.ts file, renames all instances. this is obviously wrong. Options, 1. error (obviously not helpful), 2. only rename local symbol (better, but leaves the code in an invalid state), 3. rename local import and add `as oldname` clause to the import declaration as needed (looks like the best solution). This is similar to the issue related to https://github.com/Microsoft/TypeScript/issues/7458, except that this issue adds renaming the import alias.