Robotics Systems Types

Sorry, but this cannot be merged without modification because of the following problems:

• Please split off the part-of-speech tag change and make a separate issue.
• Part-of-speech tag
  • Please rename the field to part_of_speech_tag
  • Please rename and/or document the enum members. Most of the abbreviations are completely unclear to non-experts. Alternatively or in addition to that, if this is a standard tagging scheme, add a reference to a description of the scheme.
• Dependency Tree
  • The comment does not explain what corenlp or a corenlp dependency tree is or where the reader can find more information about those things.
  • Why is the dependency tree a string and not tree data structure? (Same goes for grammar tree, btw. But that may be too late)
  • If it has to be string, the comment should explain its structure and interpretation.

split off additions and made commentary better.
also renamed the "dependency"-tree to more generic "parse"-tree.
it is a string because we want to store the parse-results in xml format and use xpath on it.