Issue #153: fix warnings about usage of deprecated "dplyr::arrange_()" and "dplyr::select_()" functions

[aalucaci]

Description

This pull request contains 2 commits. The first commit removes trailing white spaces. The white space removal was done via the sed command indicated in the commit message. The reason I did the commit: my RStudio deletes the trailing white spaces by default. To avoid cluttering, I created this separate commit. Feel free to disregard this commit if you consider it unnecessary.

Motivation and Context

This pull request fixes the issue 153 concerning warnings about usage of the deprecated dplyr::arrange_() and dplyr::select_() functions.

How Has This Been Tested?

I checked my changes by checking the package (devtools::check()) and ensuring that there are no errors.

Screenshots (if appropriate):

Types of changes

• [ x] Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x ] My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• [x ] All new and existing tests passed.

[CLAassistant]

All committers have signed the CLA.