Bump from Velodyne version 1.1.2 (Nov 2013) to the latest release,
1.2.0 (Aug 2014).  This version includes a fix to support yaml-cpp
1.5+ so resolves #325 [1].

[1] https://github.com/bmwcarit/meta-ros/issues/325



Signed-off-by: Ash Charles <ashcharles@gmail.com>