use perl instead of sed in style checks for portability to MacOS

[baperry2]

Summary

sed -i does not function the same for GNU and BSD sed and a simple portable command between the two is apparently not possible. Therefore, the style check scripts do not work by default when running on Macs, unless the user installs gsed and aliases sed to run that instead. For portability,perl can be used instead of sed.

Additional background

Proposed solution taken from here: https://stackoverflow.com/questions/4247068/sed-command-with-i-option-failing-on-mac-but-works-on-linux

Checklist

The proposed changes:

• fix a bug or incorrect behavior in AMReX
• add new capabilities to AMReX
• changes answers in the test suite to more than roundoff level
• are likely to significantly affect the results of downstream AMReX users
• include documentation in the code and/or rst files, if appropriate