Change functions description_set/get; what do you think?

  we can have descriptions for set and get property, so add hash into
  function to use it like data_set/get
  T.e.
  for property:
    - database_function_description_get(fid, "comment")
      or
    - database_function_description_get(fid, "comment_set")

    - database_function_description_get(fid, "comment_get")

  for set property:
    - database_function_description_get(fid, "comment")
      or
    - database_function_description_get(fid, "comment_set")

  for get_property:
    - database_function_description_get(fid, "comment")
      or
    - database_function_description_get(fid, "comment_get")

  for method:
    - database_function_description_get(fid, "comment")
add description for class
TODO updated
save constructors into separate list + refactor