Crane is not properly displayed when towerbox, jibbox and counterjibbox are unchecked

[castn]

Since 80abd15 commit, only the part of the crane is updated which has a checked box. This means that only the tower is updated if only towerBox is checked and so on.

1. If towerBox and jibBox are checked on startup and then the configurations are applied. The crane will be created as expected. If you then uncheck jibBox, I would expect that only the tower is build. This is the case, the tower updates. But the jib is still in the plot visible and not removed as expected.
2. If no towerBox is selected jibBox and counterJibBox will throw error inside check_config() due to the tower_width is null. I would expect it to display a proper jib or counter jib.

[castn]

To fix 2. jib and counterJib needs its own width. This would resolve it

[eZSnake]

2 is easy to implement but could cause the crane to look quite weird Alternative: don't have checkboxes and always have everything generate bc otherwise it isn't a crane

[eZSnake]

1: yes because it still contains the old data and 'apply' builds the entire crane currently this would be another problem resolved by removing the ability to generate only parts of the crane it would also cause a heap of other issues if currently 'correctly' implemented

[castn]

Fix issue in 1d28e92eac3e4c8ecd512dafccdbb595920d6fde by removing option to disable jib or counter jib as well as tower entirely.