We should call imu.update() before asking for accel/gyro values so that we get...

We should call imu.update() before asking for accel/gyro values so that we get timely, fresh numbers.

Most other consumers of the accel/gyro values should be asking us for them anyway.  At that point, what they are getting are the values we sampled here.

git-svn-id: https://arducopter.googlecode.com/svn/trunk@1376 f9c3cf11-9bcb-44bc-f272-b75c42450872