4 new commits pushed to

<https://github.com/RTimothyEdwards/magic/tree/master|master>

by RTimothyEdwards

<https://github.com/RTimothyEdwards/magic/commit/13a1bfcc2e30f063b63fd34be501820b77677bf5|13a1bfcc>

- Discovered that reading in polygons as subcells and then flattening

<https://github.com/RTimothyEdwards/magic/commit/e5813f51fa65a3fda7be737e8b7a36b7ed949091|e5813f51>

- Added a new option "-doinplace" for the "flatten" command. This

<https://github.com/RTimothyEdwards/magic/commit/edecd810469ccf7068c62feae8cebaf39d16718c|edecd810>

- Modified the toolkit add_selection procedure to take an extra

<https://github.com/RTimothyEdwards/magic/commit/677cd8ab5e1ec9c3e04c101149885761d02ec63b|677cd8ab>

- Implemented simple drain and source length calculations as device RTimothyEdwards/magic