STYLE: Remove trailing white-spaces and fix indentation in `CMakeLists.txt`

[jcfr]

Removing trailing whitespaces streamline comparison between revisions of the code.

For additional references:

• https://stackoverflow.com/questions/3492234/benefits-of-stripping-trailing-white-spaces
• https://web.archive.org/web/20171026090011/https://blog.codinghorror.com/whitespace-the-silent-killer/

---

Once integrated, the commits prefixed with STYLE: should be added to a file called .git-blame-ignore-revs file.

This file lists revisions that should be ignored when considering attribution for the actual code written. Code style changes should not be considered as modifications with regards to attribution.

To see clean and meaningful blame information.

$ git blame important.py --ignore-revs-file .git-blame-ignore-revs

To configure git to automatically ignore revisions listed in a file on every call to git blame.

$ git config blame.ignoreRevsFile .git-blame-ignore-revs

Based on:

• https://github.com/InsightSoftwareConsortium/ITK/commit/3a969e556af074614f75eeb59befbe83e410b47c.
• https://github.com/Slicer/Slicer/commit/ec82a93f0c310d0c4508045bd3e934f53c7d2d12

[jcfr]

re: https://github.com/DCBIA-OrthoLab/SlicerAutomatedDentalTools/issues/59

[allemangD]

I fixed some of these in #60 - see 56015b0 - but I only fixed files that I already touched in that PR.

I suggest merging #60 first, rebasing this PR, then merge. Since I only reformatted already-modified files it's probably fine not to worry about blame ignore for #60. I'll go ahead and add blame ignore for this PR once it's rebased and merged.

[allemangD]

With #60 and #69 things have diverged enough that rather than trying to rebase these changes, I'll just merge #68 and then perform these same reformatting tasks on the new, updated, main.