build/lib/tsb/builder.ts/LanguageServiceHost/removeScriptSnapshot
class LanguageServiceHost:	removeScriptSnapshot(filename: string): boolean {
		this._filesInProject.delete(filename);
		this._filesAdded.delete(filename);
		this._projectVersion++;
		filename = normalize(filename);
		delete this._fileNameToDeclaredModule[filename];
		return delete this._snapshots[filename];
	}