Merge pull request #42 from 130s/groovy-devel

DIO related (adjust to new DIO assignment. A bug fix).
More hands comments and refactoring variable names

(abs_hand_command.py) Add more api doc

More apidoc cleaning
Generalize hands DIO variables, and add a method to reassign them in the derived classes.

Refactoring) variable names more specialized.
(nextage_ros_bridge/base_hands.py) minor documenting
Update CHANGELOG.rst
0.2.8
(nextage_ros_bridge) Fixed installation of missing py files