bump version to 315.2.5

OKでしたらタグもお願いします．
```
0e80a4d (Stabilizer) : Add data port for Stabilizer root pos and rot debugging
07a1634 (AutoBalancer, Stabilizer, hrpsys_config.py) : Add data port for swing and support period remain time\
s and connect it between abc and st
1a9b4d8 (Stabilizer) : Use force difference control
7b02bd9 Update README.md
84fd5b3 replaces secure line and branch name(ghdoc->master)
cb4527f use CPython as default python and add hrpsys_config.py
fad511e (.travis.yml) add automatic push to gh-pages
9bb642f (.travis.sh) add graphbiz to install
b57bb6e (hrpsys py) move api doc for some methods from downstream.
94e0cfc (rtm.py) Error message minor improvement
bb119e3 (hrpsys_config.py) : Enable to use RMFO on robots without imu. Connect RPY port only if it exists.
eb0a5f7 change list of list of str
43d6761 update docstrings of setTargetPose and setTargetPoseRelative
12bfb8a use 'list of ...' instead of '[...]' to describe @type/@rtype
32f053a rename @type names to match method arguments
7b966a1 fix sphinx syntax
f63f927 uses round instead of floor
69e0b22 (Stabilizer) : Add both foot contact checker and update force z control
6a1aaa6 (Stabilizer,hrpsys_config.py) : Add debug port for Stabilizer compensation
a9188e5 (samplerobot_impedance_controller) : Add set ref force and moment example for impedance controller
66865f8 adds a new component, AverageFilter
29bfe86 (AutoBalancer, GaitGenerator, Stabilizer, sample) : Fix end effector name, e.g., :rarm => rarm. This \
change is based on JointGroup name discussed in https://github.com/fkanehiro/hrpsys-base/issues/232
88e56bc (KalmanFilter) : Inhibit debug print in KalmanFilter.h
488715b (KalmanFilter) : Add DEBUG to control printing of KalmanFilter
7bf7b3e enable to set reference frame in get{Reference,Current}{Pose,Position,Rotation,RPY}, see #297
48a9d17 update KalmanFilter. KF -> EKF and RPY -> Quaternion

```