Merge pull request #2 from blandry/master

Simple flapping motion
improved pigeon_3 URDF
Rotated pigeon model to make more sense in drake. Many versions were added, though most are broken and will be deleted later. The current version (pigeon_8) has all of the previous springs, transmissions, etc. and works.
copied runFlapping and runPassive into pigeon_8 directory and modified runFlapping to account for the change of orientation. runPassive has not been changed yet
Added list of measurements we want from Harvard
fixed minor descrepancies between the left and right sides of the pigeon so as to reduce sidways tumbling
script to find trim position