Adds command line option (true by default) to use system time.
Merge remote-tracking branch 'origin/master' into fix/visual-only-calibration
Merge branch 'master' into fix/visual-only-calibration
IMU data verification.
Frames should be skipped until IMU data is available. Also, if between two frames there is no IMU data, a FATAL error is thrown.
Merge pull request #7 from arpg/fix/visual-only-calibration

Fix/visual only calibration