Revise get functions & (minor) fix typos in the comments

[LimHyungTae]

This PR is a bit subtle, but I revised the functions.

• 040a6a3: By my mistake, getNormals was wrongly put as a private function. So I move the place
• e3d6374: Add the getInputOrderedTranslationInliers function to easily visualize the actual inliers after the whole pipeline.
• 3299678: By my silly mistake, I noticed that it should have been written as Quatro, but it remained as FGR due to copy and modification of the comments (here. While I modifying that typo, I also checked typos in the include folder and upload them

[LimHyungTae]

To better understand, I simply drew what getInputOrderedTranslationInliers is for as an example (see e3d6374). In turn, a user might want to get {1, 2, 7}, which corresponds to the order of raw src (or tgt), not {0, 1, 3}, which is returned by the getTranslationInliers function.

[jingnanshi]

👍