System output does not work at the current versions of TS and system.js. Will revisit after upgrading TS. Removes unused traceur tooling. Closes #3974
This will allow it to be reused in other doc gen configurations
This means that we can now run just the d.ts file generation by running: ```bash gulp docs/typings ``` In addition the type definition generation was messing with the other docs tasks so separating it also fixes problems there.