Update Yarp tweak version for tracking IOpenLoop API change

The IOpenLoopControl interface API has changed (check https://github.com/robotology/yarp/commit/52fedf60f9b903d5c6c3076ddcbee5926b7a03e4), we can change the tweak version so software using the new API can depend on a specific yarp version. 
I guess it will make sense to make a development release when the InteractionMode branch is merged with the master, but in the meanwhile it will be handy to increase the tweak version.
Merge pull request #197 from traversaro/patch-1

Update Yarp tweak version for tracking IOpenLoop API change