Also fix a crash bug due to setStarted and setDone.
Change-Id: Ib9b069fe4b7e5d1fc359f48e44b4032dd8249428
(cherry picked from commit 9ef190ed3ecd66d12617ad96e927ff34251395a2)
1. add gcode conflict checker
2. add a new command line option: --no_check. When it's provided, gcode
conflict check is skipped.
Change-Id: I6feafca8c5fa6c3c5eae1f0e541ce59d2f03dedf
(cherry picked from commit 5a39afb64e826a960d9673dcada89d02d62b3911)