Fix tscoder dependencies

[Lorenzobattistela]

• Pass dependencies command as a system property to run the correct command for the language
• Get the dependent files using the proper command -> a list of absolute, resolved paths
• Read the contents of those paths as context

Tscoder fixes:

• Output a list of absolute paths, e.g import { b } from './a' assuming the path of current file is /home/this_path/, the return of tscoder is ['home/this_path/a']
• Document tscoder
  It works for dependent / independent imports, does not crash on circular dependencies. Returns only the file and not what it imports from the file.