[20160921] Hand Position Control

Right hand moves up and down.

Note:

1. When I change the implementation from

Lambda = Lambda_inv. inverse() , which means Eigen3's built-in inverse matrix function

to

sejong:pseudoInverse(Lambda_inv, 1.e-8, Lambda, 0), which means singular decomposition based hand-mad matrix inverse function,

the prioritized tasks starts to work.

2. Add velocity feedback is essential to stabilize the motion. I don't exactly understand why it is such important.

3. Lubuntu lost some python package (rospkg, empy ...)

Whenever I meet the issues, I did 'pip install {package_name}'

I don't have any problem now to run our program.